Monday, 03 August 2026

PYQ references used by both prompts 13 included 1 excluded

Flagged questions are excluded from both Study Notes and PPT references until corrected in Paper Analyzer.

Included ID 6648 · 2024 · 3 mark(s)

A) You have a stack named BooksStack that contains records of books. Each book record is represented as a list containing book_title, author_name, and publication_year.
Write the following user-defined functions in Python to perform the specified operations on the stack BooksStack:
(I) push_book(BooksStack, new_book): This function takes the stack BooksStack and a new book record new_book as arguments and pushes the new book record onto the stack.
(II) pop_book(BooksStack): This function pops the topmost book record from the stack and returns it. If the stack is already empty, the function should display "Underflow".
(III) peep(BookStack): This function displays the topmost element of the stack without deleting it. If the stack is empty, the function should display 'None'.

Stack Data Structure → Stack concept and operations using list

Included ID 6649 · 2024 · 3 mark(s)

B) Write the definition of a user-defined function push_even(N) which accepts a list of integers in a parameter N and pushes all those integers which are even from the list N into a Stack named EvenNumbers.
Write function pop_even() to pop the topmost number from the stack and returns it. If the stack is already empty, the function should display "Empty".
Write function Disp_even() to display all elements of the stack without deleting them. If the stack is empty, the function should display 'None'.
For example:
If the integers input into the list VALUES are: [10, 5, 8, 3, 12]
Then the stack EvenNumbers should store: [10, 8, 12]

Stack Data Structure → Stack concept and operations using list

Included ID 6165 · 2024 · 5 mark(s)

A list contains the details of Employees working in an organization. Write the following user defined functions in Python to perform the given operations:
(i) Push_Employee(EmpList) : To push the details of the employees into the stack EmpStack who are working in Admin department.
(ii) Pop_Employee() : To pop the elements from the stack and display. Also display "Empty" when there are no elements in the stack.

For example:
If the list contains the details as:
['EMP01','Raj','Admin']
['EMP02','Shreya','HR']
['EMP03','Rohan','Admin']
['EMP04','Anita','Admin']
['EMP05','Priya','HR']

The output should be:
Anita
Rohan
Empty

Stack Data Structure → Stack concept and operations using list

Excluded ID 6166 · 2024 · 5 mark(s)

Write a user defined function in Python named write_data() to write the data in a CSV file Stock.csv with field names Product_Name, Product_ID, Quantity, Price as shown below:

| Product_Name | Product_ID | Quantity | Price |
|--------------|------------|----------|-------|
| Keyboard | P101 | 10 | 800 |
| Mouse | P102 | 12 | 600 |
| Monitor | P103 | 5 | 5000 |
| CPU | P104 | 8 | 10000 |

(ii) pop_record(): To pop the elements from the stack and display. Also display "No Record" when there are no elements in the stack.

Stack Data Structure → CSV file read write and search, Stack concept and operations using list

Awaiting categorisation review

Included ID 6167 · 2024 · 5 mark(s)

Write the following Python functions:
(i) push_record(): To push the product details of the products whose price is more than 500 into the stack Record.

(ii) pop_record(): To pop the elements from the stack and display. Also display "No Record" when there are no elements in the stack.

Stack Data Structure → Stack concept and operations using list

Included ID 6204 · 2025 · 3 mark(s)

Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all elements which contain the substring 'books' (case insensitive) onto the list SBOOKS.

Stack Data Structure → Stack concept and operations using list

Included ID 6205 · 2025 · 3 mark(s)

Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all even numbers in the list on to the list EVENLIST.

Stack Data Structure → Stack concept and operations using list

Included ID 6407 · 2025 · 3 mark(s)

(a) A stack named KeyStack contains records of some computer keyboards. Each record is represented as a list containing Make, Keys, Connectivity. The Make and Connectivity are strings, and Keys is an integer. For example, a record in the stack may be ('Hitech', 105, 'USB').
Write the following user-defined functions in Python to perform the specified operations on KeyStack :
(I) push_key(KeyStack, new_key) : This function takes the stack KeyStack and a new record as arguments new_key and pushes this new record onto the stack.
(II) pop_key(KeyStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow".
(III) isEmpty(KeyStack) : This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.

(II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
(III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.

Stack Data Structure → Stack concept and operations using list

Included ID 6408 · 2025 · 3 mark(s)

(b) Write the following user-defined functions in Python :
(I) push_vowels(S,St) : Here S is a string and St is a list representing a stack. The function should push all the vowels of the string S onto the stack St. For example, if the string S is "Easy Concepts", then the function push_vowels() should push the elements 'E','a','o','e' onto the stack.

(II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
(III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.

Stack Data Structure → Stack concept and operations using list

Included ID 6696 · 2025 · 3 mark(s)

A list containing records of products as
L = [("Laptop", 90000), ("Mobile", 30000), ("Pen", 50), ("Headphones", 1500)]
Write the following user-defined functions to perform operations on a stack named Product to:
I. Push_element() – To push an item containing the product name and price of products costing more than 50 into the stack.
Output: [('Laptop', 90000), ('Mobile', 30000), ('Headphones', 1500)]
II. Pop_element() – To pop the items from the stack and display them. Also, display "Stack Empty" when there are no elements in the stack.
Output:
('Headphones', 1500)
('Mobile', 30000)
('Laptop', 90000)
Stack Empty

Stack Data Structure → Stack concept and operations using list

Included ID 6212 · 2025 · 5 mark(s)

A list contains the names of boys who participated in an inter school level swimming competition. Write the following user defined functions in Python to perform given operations:
(i) Push_element(Boys) : To push the names of boys in the stack where the length of the name is more than 5 characters.
(ii) Pop_element() : To pop the elements from the stack and display them. Also display "Stack Empty" when there are no elements in the stack.

For example:
If the list of boys who participated in the competition is :
['Rohit', 'Rahul', 'Rishabh', 'Virat', 'Hardik']
The stack should contain
['Rishabh', 'Hardik']
The output should be displayed as:
Hardik
Rishabh
Stack Empty

Stack Data Structure → Stack concept and operations using list

Included ID 6255 · 2026 · 3 mark(s)

(a) A stack named FruitStack, implemented using list, contains records of some fruits. Each record is represented as a dictionary with keys 'Name', 'Origin', 'Price', and 'Expiry'.
A sample record is given here :
{'Name':'Apple', 'Origin':'France', 'Price':120, 'Expiry':'12-08-2025'}
Write the following user-defined functions in Python to perform the specified operations on FruitStack :
(i) push_fruit(FruitStack, Fruit): This function takes the stack FruitStack and a new record Fruit as arguments and pushes the record stored in Fruit onto FruitStack if the Price is less than 100.
(ii) pop_fruit(FruitStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display "UNDERFLOW".
(iii) display(FruitStack) : This function displays all the elements of the stack starting from the topmost element. If the stack is empty, the function should display 'EMPTY STACK'.

Stack Data Structure → Stack concept and operations using list

Included ID 6256 · 2026 · 3 mark(s)

(b) Write a Python program to accept 10 integers from the user. If the entered number is a three-digit even integer, push it onto a stack. After all inputs are taken, pop all the three-digit even integers from the stack and display them. For example, if the user enters 12, 31, 320, 457, 6, 92, 924, 220, 1, 218, then the stack should contain :
320, 924, 220, 218
and the output of the program should be :
218 220 924 320

Stack Data Structure → Stack concept and operations using list

Included ID 6257 · 2026 · 3 mark(s)

(a) Write the output of the following code :
def Exam2026(given) :
    new=[]
    for ch in given[1:-1]:
        if ch.isupper():
            new.reverse()
        elif ch not in new:
            new.append(ch)
        elif ch in new:
            new.pop()
    print(new)
Exam2026("Gold-24Medals")

Stack Data Structure → Stack concept and operations using list

.txt

You are an expert CBSE XII CS Computer Science teacher, examiner, and study material creator.

===========================================
SCOPE — READ BEFORE GENERATING ANYTHING
===========================================
Today's lecture covers ONE topic only: "Stack concept and operations using list"
Lecture number 42 of 91 | Duration: 35 minutes | Board: CBSE
Chapter: Computational Thinking and Programming – 2

HARD RULE: Every piece of content you generate — notes, examples, questions, tips —
must be directly relevant to "Stack concept and operations using list" only.
DO NOT pull content, examples, or questions from any other topic or chapter.

LECTURE MODE: SUBTOPIC PYQ PRACTICE
- Scope: "Stack concept and operations using list" only.
- Do not reteach the topic from scratch. Use a short recap only when a PYQ needs it.
- Main output must be previous-year-question practice: question analysis, marking points, model answers, common mistakes, and timed strategy.
- Use the 13 real PYQ record(s) provided below as the source of truth. Do not fabricate board years, marks, or questions.

===========================================
SECTION 1: LECTURE INFORMATION
===========================================

Class: XII CS | Subject: Computer Science | Board: CBSE
Topic: Stack concept and operations using list PYQ part 2
Subtopics to cover today:
- Stack concept and operations using list

Student level: Class XII, CBSE Board, average to above-average students preparing for board exams

===========================================
SECTION 2: TEACHER'S REFERENCE NOTES
===========================================

Stack concept and operations using list PYQ part 2

PYQ PRACTICE SCOPE: Stack concept and operations using list.
Concept ID: U1_STACK_LIST_OPS.
Use only previous-year questions whose concept_ids include U1_STACK_LIST_OPS.

Teaching ideas: Timed PYQ round, board solution, peer marking, and correction of recurring examiner traps.

===========================================
SECTION 3: EXAM FREQUENCY DATA (Year-wise)
===========================================

Teaching priority: HIGH
High-yield concepts: Stack concept and operations using list

| Year | Questions | Marks |
|------|-----------|-------|
| 2024 | 4 | 16 |
| 2025 | 6 | 20 |
| 2026 | 3 | 9 |
| **Total** | **13** | **45** |

===========================================
SECTION 4: ACTUAL PREVIOUS YEAR QUESTIONS
(Scope: "Stack concept and operations using list" only — 13 questions from board papers)
===========================================

PYQ LECTURE RULE: use these questions as the source pool for practice.
- This pool has 13 questions: preserve and discuss ALL 13 actual PYQs in Section 7.
- Do not compress, replace, paraphrase, or skip any actual PYQ.
- Do not create substitute or newly framed questions for this small pool.
- Do not fabricate board years, marks, sections, or questions.


--- 2024 Board Exam (4 questions | 16 marks) ---

Q1. [Short Answer] [3M] [Medium] Section-C
A) You have a stack named BooksStack that contains records of books. Each book record is represented as a list containing book_title, author_name, and publication_year.
Write the following user-defined functions in Python to perform the specified operations on the stack BooksStack:
(I) push_book(BooksStack, new_book): This function takes the stack BooksStack and a new book record new_book as arguments and pushes the new book record onto the stack.
(II) pop_book(BooksStack): This function pops the topmost book record from the stack and returns it. If the stack is already empty, the function should display "Underflow".
(III) peep(BookStack): This function displays the topmost element of the stack without deleting it. If the stack is empty, the function should display 'None'.

Q2. [Programming] [3M] [Medium] Section-C
B) Write the definition of a user-defined function push_even(N) which accepts a list of integers in a parameter N and pushes all those integers which are even from the list N into a Stack named EvenNumbers.
Write function pop_even() to pop the topmost number from the stack and returns it. If the stack is already empty, the function should display "Empty".
Write function Disp_even() to display all elements of the stack without deleting them. If the stack is empty, the function should display 'None'.
For example:
If the integers input into the list VALUES are: [10, 5, 8, 3, 12]
Then the stack EvenNumbers should store: [10, 8, 12]

Q3. [Programming] [5M] [Hard] Section-D
A list contains the details of Employees working in an organization. Write the following user defined functions in Python to perform the given operations:
(i) Push_Employee(EmpList) : To push the details of the employees into the stack EmpStack who are working in Admin department.
(ii) Pop_Employee() : To pop the elements from the stack and display. Also display "Empty" when there are no elements in the stack.

For example:
If the list contains the details as:
['EMP01','Raj','Admin']
['EMP02','Shreya','HR']
['EMP03','Rohan','Admin']
['EMP04','Anita','Admin']
['EMP05','Priya','HR']

The output should be:
Anita
Rohan
Empty

Q4. [Short Answer] [5M] [Hard] Section-D
Write the following Python functions:
(i) push_record(): To push the product details of the products whose price is more than 500 into the stack Record.

(ii) pop_record(): To pop the elements from the stack and display. Also display "No Record" when there are no elements in the stack.

--- 2025 Board Exam (6 questions | 20 marks) ---

Q1. [Programming] [3M] [Medium] Section-C
Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all elements which contain the substring 'books' (case insensitive) onto the list SBOOKS.

Q2. [Programming] [3M] [Medium] Section-C
Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all even numbers in the list on to the list EVENLIST.

Q3. [Short Answer] [3M] [Medium] Section-C
(a) A stack named KeyStack contains records of some computer keyboards. Each record is represented as a list containing Make, Keys, Connectivity. The Make and Connectivity are strings, and Keys is an integer. For example, a record in the stack may be ('Hitech', 105, 'USB').
Write the following user-defined functions in Python to perform the specified operations on KeyStack :
(I) push_key(KeyStack, new_key) : This function takes the stack KeyStack and a new record as arguments new_key and pushes this new record onto the stack.
(II) pop_key(KeyStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow".
(III) isEmpty(KeyStack) : This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.

(II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
(III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.

Q4. [Short Answer] [3M] [Medium] Section-C
(b) Write the following user-defined functions in Python :
(I) push_vowels(S,St) : Here S is a string and St is a list representing a stack. The function should push all the vowels of the string S onto the stack St. For example, if the string S is "Easy Concepts", then the function push_vowels() should push the elements 'E','a','o','e' onto the stack.

(II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
(III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.

Q5. [Programming] [3M] [Medium] Section-C
A list containing records of products as
L = [("Laptop", 90000), ("Mobile", 30000), ("Pen", 50), ("Headphones", 1500)]
Write the following user-defined functions to perform operations on a stack named Product to:
I. Push_element() – To push an item containing the product name and price of products costing more than 50 into the stack.
Output: [('Laptop', 90000), ('Mobile', 30000), ('Headphones', 1500)]
II. Pop_element() – To pop the items from the stack and display them. Also, display "Stack Empty" when there are no elements in the stack.
Output:
('Headphones', 1500)
('Mobile', 30000)
('Laptop', 90000)
Stack Empty

Q6. [Programming] [5M] [Hard] Section-D
A list contains the names of boys who participated in an inter school level swimming competition. Write the following user defined functions in Python to perform given operations:
(i) Push_element(Boys) : To push the names of boys in the stack where the length of the name is more than 5 characters.
(ii) Pop_element() : To pop the elements from the stack and display them. Also display "Stack Empty" when there are no elements in the stack.

For example:
If the list of boys who participated in the competition is :
['Rohit', 'Rahul', 'Rishabh', 'Virat', 'Hardik']
The stack should contain
['Rishabh', 'Hardik']
The output should be displayed as:
Hardik
Rishabh
Stack Empty

--- 2026 Board Exam (3 questions | 9 marks) ---

Q1. [Short Answer] [3M] [Medium] Section-C
(a) A stack named FruitStack, implemented using list, contains records of some fruits. Each record is represented as a dictionary with keys 'Name', 'Origin', 'Price', and 'Expiry'.
A sample record is given here :
{'Name':'Apple', 'Origin':'France', 'Price':120, 'Expiry':'12-08-2025'}
Write the following user-defined functions in Python to perform the specified operations on FruitStack :
(i) push_fruit(FruitStack, Fruit): This function takes the stack FruitStack and a new record Fruit as arguments and pushes the record stored in Fruit onto FruitStack if the Price is less than 100.
(ii) pop_fruit(FruitStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display "UNDERFLOW".
(iii) display(FruitStack) : This function displays all the elements of the stack starting from the topmost element. If the stack is empty, the function should display 'EMPTY STACK'.

Q2. [Short Answer] [3M] [Medium] Section-C
(b) Write a Python program to accept 10 integers from the user. If the entered number is a three-digit even integer, push it onto a stack. After all inputs are taken, pop all the three-digit even integers from the stack and display them. For example, if the user enters 12, 31, 320, 457, 6, 92, 924, 220, 1, 218, then the stack should contain :
320, 924, 220, 218
and the output of the program should be :
218 220 924 320

Q3. [Output Prediction] [3M] [Medium] Section-C
(a) Write the output of the following code :
def Exam2026(given) :
    new=[]
    for ch in given[1:-1]:
        if ch.isupper():
            new.reverse()
        elif ch not in new:
            new.append(ch)
        elif ch in new:
            new.pop()
    print(new)
Exam2026("Gold-24Medals")

===========================================
===========================================
QUESTION PATTERN BANK (What the board actually asks for THIS topic)
===========================================
Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: Stack concept and operations using list
  Pattern: Output Prediction=1, Programming=6, Short Answer=6 | Marks: 3M=10, 5M=3 | Total: 13 questions
  [Short Answer] [3M] [Medium] × 4
    → Core concept of Stack concept and operations using list
  [Programming] [3M] [Medium] × 3
    → Core concept of Stack concept and operations using list
  [Programming] [5M] [Hard] × 2
    → Output/result interpretation for the current concept
  [Short Answer] [5M] [Hard]
    → Core concept of Stack concept and operations using list
  [Programming] [3M] [Medium]
    → Output/result interpretation for the current concept
  [Short Answer] [3M] [Medium]
    → Output/result interpretation for the current concept
  [Output Prediction] [3M] [Medium]
    → Output/result interpretation for the current concept


===========================================
===========================================
IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
===========================================
| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | Stack concept and operations using list | 115 | 13 | 45M | 2026, 2025, 2024 | CRITICAL |

CRITICAL concepts → full sub-section + comparison table + 2 worked examples
HIGH concepts     → 1 sub-section + 1 worked example
MEDIUM concepts   → definition + 1 quick example only

===========================================
EXAMINER FINGERPRINT — TRAPS TO COVER INTERNALLY
===========================================

Use the exam-frequency input and actual previous-year questions to identify traps, marking points, and common mistakes. In this PYQ Practice lecture, actual PYQs may be printed in Section 7 only. Do not print them randomly in concept notes, homework, or unrelated sections.

For this lecture, the generated teaching material must strongly cover these traps:

No static trap list exists yet for "Stack concept and operations using list". Self-generate 4–7 traps from:
- actual question patterns for Stack concept and operations using list
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

Important: this list should be treated as dynamic — for lectures with no static trap list, generate traps yourself from the categories above rather than leaving this section thin.
===========================================
YOUR TASK — Generate a complete classroom-ready teaching package
===========================================

Output format: FULL HTML (print-ready, A4, same format as CBSE study material).
Use the CSS classes below. NO plain Markdown — use HTML elements only.

HTML STRUCTURE TO GENERATE:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>Stack concept and operations using list PYQ part 2 — Lecture 42</title>
<style>
/* ── PRINT SETUP ── */
@page { size: A4; margin: 12mm 14mm 12mm 14mm; }
* { box-sizing: border-box; }

/* ── BASE ── */
body { font-family: 'Segoe UI', Arial, sans-serif; font-size: 9.5pt; color: #1a1a2e; line-height: 1.4; background: #fff; margin: 0; padding: 0; }

/* ── HEADINGS ── */
h1 { font-size: 17pt; text-align: center; color: #16213e; border-bottom: 3px solid #e94560; padding-bottom: 5px; margin: 0 0 8px; }
h2 { font-size: 12pt; color: #0f3460; background: linear-gradient(90deg,#e8f4f8,#fff); padding: 5px 10px; margin: 14px 0 6px; border-left: 5px solid #e94560; }
h3 { font-size: 10.5pt; color: #16213e; border-bottom: 1.5px dashed #ccc; padding-bottom: 3px; margin: 10px 0 4px; }

/* ── CONTENT BOXES ── */
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.key-box { background:#fff8e1; border-left:3px solid #f9a825; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.key-box ul { margin:3px 0 0 12px; padding:0; }
.key-box li { margin:2px 0; }
.example-box { background:#f3e5f5; border-left:3px solid #7b1fa2; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box { background:#ffebee; border-left:3px solid #c62828; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box::before { content: "⚠ EXAMINER TRAP: "; font-weight:bold; color:#e65100; }
.tip-box { background:#e8f5e9; border-left:3px solid #2e7d32; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
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.pyq-box .pyq-meta { font-size:7.5pt; color:#e65100; font-weight:bold; margin-bottom:3px; }
.mcq-box { background:#f8f9fa; border:1px solid #dee2e6; padding:6px 10px; margin:5px 0; border-radius:4px; font-size:9pt; }
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.options .why { font-size:8pt; color:#555; margin-left:8px; font-style:italic; }
.self-test-box { background:#e8eaf6; border:1px dashed #5c6bc0; padding:6px 10px; margin:6px 0; border-radius:4px; font-size:9pt; }
details summary {
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  border-radius:4px; font-size:8.5pt; font-weight:600; user-select:none;
  list-style:none;
}
details summary::-webkit-details-marker { display:none; }
details[open] > summary { background:#c5cae9; }
details > *:not(summary) { margin-top:6px; }

/* ── CODE ── */
pre {
  background:#f8f9fa;
  color:#212529;
  border:1px solid #dee2e6;
  border-radius:4px;
  margin:4px 0;
  padding:8px 10px;
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  line-height:1.5;
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}
pre code {
  white-space:pre;
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}
code {
  font-family:'Courier New', monospace;
  font-size:0.95em;
}
.kw { color:#0000ff; } .bi { color:#267f99; } .st { color:#a31515; }
.cm { color:#008000; } .nm { color:#098658; } .fn { color:#795e26; }
.va { color:#001080; }

/* ── TABLES ── */
table { border-collapse:collapse; width:100%; margin:5px 0; font-size:8.5pt; }
th, td { border:1px solid #bbb; padding:3px 6px; text-align:left; }
th { background:#eeeeee; font-weight:bold; color:#333; }
tr:nth-child(even) { background:#fafafa; }
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/* ── B&W MODE OVERRIDES ── */
body.bw-mode { background:#fff !important; color:#000 !important; }
body.bw-mode .def-box, body.bw-mode .key-box, body.bw-mode .example-box,
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<script>
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<!-- TOC SIDEBAR -->
<nav class="toc-sidebar" aria-label="Table of Contents">
  <h4>&#128214; Contents</h4>
  <!-- TOC links auto-built by JS above -->
</nav>

<!-- MAIN CONTENT -->
<div class="main-content">

Generate these sections in order (all inside the main-content div):

<h1 id="top">Stack concept and operations using list PYQ part 2 — Lecture 42</h1>
<p style="text-align:center;color:#555;font-size:8.5pt;">CBSE | XII CS | Computational Thinking and Programming – 2 | 35 min</p>

<h2 id="s1">1. Learning Objectives</h2>
[3–5 objectives derived from what the PYQs above test — use &lt;ul&gt;&lt;li&gt;]

<h2 id="s2">2. 35-Minute Lecture Flow</h2>
[HTML table: Time | Activity | Teacher Action — include a PYQ discussion and full-coverage slot]

<h2 id="s3">3. Quick Concept Recap</h2>
[Keep this section short. Do NOT reteach the full topic from scratch.
Include only the rules needed to solve the PYQs — i.e. the traps listed in the
EXAMINER FINGERPRINT section above (for this lecture: Stack concept and operations using list).
Use .def-box and .key-box only. Add at most one tiny example if needed.
Do not include long theory, long programming tasks, or unrelated examples.]

<h2 id="s4">4. Examiner Tricks &amp; Common Mistakes</h2>
[One .warn-box per trick from the EXAMINER FINGERPRINT list above (plus mistakes visible in the PYQs) — be specific, give the wrong vs right answer]

<h2 id="s5">5. Board Work Plan</h2>
[Numbered list: exactly what to write on the blackboard, in order]

<h2 id="s6">6. Classroom Practice Questions</h2>
[Modelled on PYQ style. CRITICAL: every answer MUST be inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; — never expose the answer directly.

Practice questions must follow the difficulty and mark pattern of the actual PYQ pool.

For this topic:
* 3×1M MCQ
* 5×1M/2M Short Answer
* Include 2×3–5M programming practice (the PYQ pool contains long-answer/programming patterns)
* Include 1 HOTS question (the PYQs reveal a genuine higher-order trap)

Every question must be based on one of the traps from Section 4 (EXAMINER FINGERPRINT).
Every answer must be hidden inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;.

MCQ structure:
&lt;div class="mcq-box"&gt;
  &lt;b&gt;Q1.&lt;/b&gt; Question text?&lt;br&gt;
  &lt;ul class="options"&gt;
    &lt;li&gt;a) ...&lt;/li&gt;
    &lt;li&gt;b) ...&lt;/li&gt;
    &lt;li&gt;c) ...&lt;/li&gt;
    &lt;li&gt;d) ...&lt;/li&gt;
  &lt;/ul&gt;
  &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    &lt;ul class="options"&gt;
      &lt;li class="wrong"&gt;a) ... — reason why wrong&lt;/li&gt;
      &lt;li class="correct"&gt;b) ... ✓ — reason why correct&lt;/li&gt;
      ...
    &lt;/ul&gt;
  &lt;/details&gt;
&lt;/div&gt;
(Note: options list shown WITHOUT .correct/.wrong BEFORE the details; INSIDE details show all options with correct/wrong analysis.)

Short-answer structure:
&lt;div class="self-test-box"&gt;&lt;b&gt;Q4.&lt;/b&gt; Question&lt;br&gt;&lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;Full answer&lt;/details&gt;&lt;/div&gt;

Dynamic distribution rule:
* If actual PYQs are only 1M/2M, keep generated practice mostly 1M/2M.
* If actual PYQs include 3M/5M programming, include 3M/5M programming practice.
* Never force HOTS or programming questions when the provided PYQ pool does not support them.]

<h2 id="s7">7. PYQ Discussion / Full Coverage (13 source questions)</h2>
[This source pool has 13 actual PYQs.
PYQ COVERAGE RULE:
  - This pool has 13 PYQs, so include and discuss ALL 13 actual PYQs in Section 7.
  - Do not compress, replace, paraphrase, or skip any actual PYQ in this small pool.
  - Compression is allowed only when the source pool has more than 15 questions.
  - Never fabricate board years, marks, sections, or question text.
For every fully discussed actual PYQ include:
  year · marks · type · full question text · concept tested · model answer inside &lt;details&gt; · common mistake inside &lt;details&gt;
Order questions Easy to Tough; within difficulty, order 1 mark → 2 marks → 3 marks → 4/5 marks.
Use this structure for actual PYQ examples:
  Use this structure for each question:
  &lt;div class="pyq-box"&gt;
    &lt;div class="pyq-meta"&gt;[YEAR] · [X] Marks · [TYPE] · Section-[S]&lt;/div&gt;
    &lt;b&gt;Q.&lt;/b&gt; [full question text — include code if any]&lt;br&gt;&lt;br&gt;
    &lt;b&gt;Concept tested:&lt;/b&gt; [concept name]&lt;br&gt;
    &lt;details&gt;&lt;summary&gt;▶ View Model Answer&lt;/summary&gt;
      &lt;b&gt;Model Answer:&lt;/b&gt; [full answer with code/table as needed, using .kw/.bi/.st token spans in &lt;pre&gt;&lt;code&gt;]&lt;br&gt;
      &lt;b&gt;Common mistake:&lt;/b&gt; [what students get wrong — be specific]
    &lt;/details&gt;
  &lt;/div&gt;
]

<h2 id="s8">8. Student Notes (Copy-ready)</h2>
[Concise notes — every concept from PYQs — in .key-box and .def-box; self-check questions in .self-test-box with &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer&lt;/details&gt;]

<h2 id="s9">9. Homework</h2>
[Homework must follow the actual PYQ pattern for this topic:
- 3×1M MCQ
- 3×1M Short Answer
- 2×2M Short Answer only if useful for recap or trap correction
- Include 2×3–5M programming homework (the PYQ pool contains long-answer/programming patterns)
- Every homework question must map to one trap or pattern from Section 4 / Section 7.
Dynamic rule: if actual PYQs are only 1M/2M, homework stays mostly 1M/2M; if they include 3M/5M
programming, homework may include 3M/5M programming; never force unsupported marks or question types.
EVERY answer must be wrapped in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; inside .self-test-box or .mcq-box.]

<h2 id="s10">10. Exam Tips</h2>
[5 specific tips as .tip-box — derived from PYQ patterns for THIS topic only]

<h2 id="s11">11. Last-Minute Revision Cards</h2>
&lt;div class="card-grid"&gt;
[One .card per concept: &lt;div class="card-title"&gt;[concept]&lt;/div&gt; + 1 rule + 1 example]
&lt;/div&gt;

</div><!-- end .main-content -->
</body>
</html>

HARD OUTPUT RULES:
- Output ONLY the HTML document starting with &lt;!DOCTYPE html&gt;
- Do NOT wrap in markdown code fences
- Do NOT add explanatory text outside the HTML
- Use ONLY content from "Stack concept and operations using list" — zero content from other topics
- PYQ lecture: include and discuss ALL 13 actual PYQs in Section 7; do not compress, replace, paraphrase, or skip any source question
- Always finish the document completely through &lt;/html&gt;. If the answer is getting long, keep Sections 3 and 7 complete, then compact Sections 8–11 instead of truncating.
- If 15 or fewer PYQs are provided, include ALL actual PYQs in Section 7.
- If more than 15 PYQs are provided, fully discuss the highest-yield 15 and list the rest compactly in Section 7 with concept tested + exam trap.
- ANSWER HIDING (most important for student use):
    * Section 6 MCQs: options listed WITHOUT .correct/.wrong BEFORE details; full analysis only INSIDE &lt;details&gt;
    * Section 6 short/programming/HOTS questions: EVERY answer in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;
    * Section 8 self-check and Section 9 homework: EVERY answer in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    * Section 7 PYQ Discussion / Full Coverage: model answer + common mistake inside &lt;details&gt;&lt;summary&gt;▶ View Model Answer&lt;/summary&gt;
    * .pyq-box question text and concept tested stay visible outside &lt;details&gt;; only Model Answer + Common mistake are hidden inside &lt;details&gt;
    * The beforeprint JS already auto-opens all &lt;details&gt; for printing — never skip this feature
- INLINE CODE SIZE RULE:
    * Inline code (function/method names and short snippets relevant to "Stack concept and operations using list") must appear almost the same size as surrounding normal text.
    * Do NOT use fixed 8.5pt size for all &lt;code&gt; elements.
    * Use code { font-size:0.95em; } for inline code.
    * Use pre { font-size:8.5pt; } for block code.
    * Use pre code { font-size:inherit; } so code blocks remain compact.
    * Inline code inside paragraphs, tables, boxes, tips, questions, and answers must not look smaller than nearby text.
- BOX / CLASS USAGE: this is a PYQ lecture, so .pyq-box/.pyq-meta are used as shown in Section 7 above (never in theory lectures).
- All content goes inside &lt;div class="main-content"&gt;
- The &lt;nav class="toc-sidebar"&gt; is already in the template — JS auto-builds TOC links
- Print buttons (.print-bar), including Read Mode, are in the template — DO NOT add them again; they auto-hide on print
- Include the full CSS and JS exactly as given (the CODE CSS already follows the INLINE CODE SIZE RULE above).

# ENHANCED PPT GENERATION PROMPT
## Topic: Stack concept and operations using list PYQ part 2 | CBSE XII CS Computer Science

================================================
SECTION A -- VISUAL IDENTITY (READ FIRST, APPLY TO EVERY SLIDE)
================================================

COLOUR PALETTE -- "Deep Code" Theme
  Role              Hex        Name             Where Used
  Primary (dark)    #0D1B2A    Midnight Navy    Title bg, conclusion bg
  Secondary         #1B4F72    Ocean Blue       Section header cards, accent shapes
  Accent            #00D4FF    Cyan Electric    Keywords, callout borders, badges
  Neutral light     #F0F4F8    Ice White        All content slide backgrounds
  Warning/Error     #E74C3C    Alert Red        Common mistakes slide, warnings
  Success/Tip       #27AE60    Emerald Green    Tips, correct syntax, exam tips
  Text primary      #1A1A2E    Near Black       Body text on light slides
  Text on dark      #FFFFFF    Pure White       All text on dark background slides
  Text muted (dark) #C9D4E0    Slate Mist       Sub-lines / captions on navy slides

ON-LIGHT VARIANTS (use for ANY text, keyword, icon, or thin border on Ice White):
  Cyan  -> Accent-Deep  #0077A3      Emerald -> #1E8449      Red -> #C0392B
CONTRAST RULE: bright Cyan #00D4FF / Emerald #27AE60 / Red #E74C3C are for DARK
backgrounds or thick (>=4 pt) shape fills ONLY -- never for thin text, borders, or
badges on a light slide (bright cyan on Ice White is ~1.6:1 contrast = invisible
from the back row). On light slides always use the deep variants above.

COLOUR DISCIPLINE -- 60 / 30 / 10 (this is what separates "designed" from "filled-in")
  * 60% of every content slide is the Ice White background + generous EMPTY space.
    Empty space is a design element, not a slide you failed to fill.
  * 30% is ONE neutral structural element -- a single card, panel, or diagram.
  * 10% -- and NO MORE -- is the accent (Cyan Electric or one status colour). One
    accent MOMENT per slide: the focal chip, the keyword, the one arrow that
    matters. A slide where every box is coloured has NO accent -- it is noise.
  * Build depth with TINTS of one hue, never many saturated hues. A card fill is a
    6-8% tint of its header colour (pale-blue body under an Ocean Blue header),
    never a strong fill behind text. Status tints: blue 6% = definition,
    green 6% = correct/tip, red 6% = wrong/trap. Borders are 1 pt in the deep
    variant -- not thick coloured frames.
  * Navy dominates ONLY the Title and Key Takeaways slides. Never split a content
    slide 50/50 navy-vs-white -- it destroys hierarchy.

GRID & COMPOSITION (the missing rule that makes slides look intentional)
  * Lay every content slide on a 12-column grid inside the safe area with a
    consistent ~0.2 inch gutter. Snap every card, text block, icon and diagram
    edge to a column line -- never free-float objects at arbitrary x positions.
  * ONE alignment spine per slide: a single left text column (Left Icon+Text),
    two balanced 6-column halves (Two Column), or one centred focal object
    (Callout / Exam Spotlight). Do not mix three alignments on one slide.
  * Align tops and left edges across objects. Ragged, slightly-off edges are the
    #1 reason a slide reads as amateur even when nothing technically overlaps.

VISUAL HIERARCHY -- ONE FOCAL POINT PER SLIDE
  * Every slide answers "what is the ONE thing the eye lands on first?" Make that
    element the largest / boldest / the only accent-coloured object; everything
    else is visibly secondary (smaller, neutral, lighter).
  * Hierarchy comes from SCALE CONTRAST and SPACE, not from boxing everything. A
    big number, one code line, or a single diagram surrounded by white beats
    three equal-weight bordered boxes every time.
  * Reserve bold + accent colour for the focal point ONLY. If three things are
    bold and coloured, nothing is emphasised.

INFORMATION-CARRYING VISUALS (the default -- not decorative chrome)
  * The visual must MEAN something: it carries the concept, it is not an ornament
    around text. Prefer, in order: a labelled code-breakdown (one code line on a
    dark card with arrows naming each part's role), a before/after, a flow
    (input -> process -> output), a comparison table, a decision tree.
  * A rounded box with a clip-art icon beside a bullet is chrome -- it explains
    nothing and should be cut. One strong visual that teaches the idea beats four
    small decorative ones.
  * Icons: line-style, ONE consistent family, used to label SECTIONS only -- not
    one circle per bullet. An icon on every line is clutter, not design.

TYPOGRAPHY -- CLASSROOM-OPTIMISED (NON-NEGOTIABLE)
  Element             Font              Size   Weight    Notes
  Slide title         Montserrat        44 pt  Bold      Visible from back row (Arial Bold if Montserrat unavailable)
  Focal number/word   Montserrat        60+ pt Bold      The one hero element may go large for scale contrast
  Section header      Arial             32 pt  Bold      Sub-headings inside slides
  Body bullets        Calibri           28 pt  Regular   MAX 3 bullets -- min 28 pt
  Code text           Courier New       24 pt  Regular   On dark card only
  Captions/labels     Calibri           24 pt  Italic    Footer only; keep non-essential and brief

  NEVER go below 24 pt for ANY visible text.
  NEVER use Aptos, Thin fonts, or Calibri Light.
  Line spacing 1.15+. Title case for titles; sentence case for body.

VISUAL MOTIF -- "Bracket Accent" (restrained signature, not the main visual)
  * Small { } mark (Cyan Electric on dark / Accent-Deep #0077A3 on light) sits
    quietly top-left of the title -- a signature, never a slide's main visual.
  * Definitions: a single rounded callout with a 4 pt Cyan-Electric LEFT border
    only (no full frame). Code: dark #0D1B2A card, #00D4FF keywords, white rest.

DESIGN NEVER-DO LIST
  NO accent lines below titles
  NO colour bars or stripes spanning full slide width
  NO vertical sidebar stripes
  NO cream/beige backgrounds
  NO saturated colour fills behind body text (use 6-8% tints instead)
  NO icon-circle on every bullet, no clip-art decoration
  NO three competing focal points -- exactly one hero element per slide
  NO evenly-tiled grid of identical boxes whose only job is to fill the slide
  NO text-only slides -- every slide needs ONE information-carrying visual
  NO centred body text -- left-align all bullets
  NO more than 3 bullets per slide
  NO bullet longer than 10 words
  NO font below 24 pt

LAYOUT VARIETY -- ROTATE WHEN IT HELPS CLARITY
  Layout Name         When to Use
  Full-bleed Dark     Title slide, Key Takeaways slide
  Left Icon+Text      Theory slides -- icon circle left, bullets right
  Two Column          Comparisons (push vs pop, stack (LIFO) vs queue (FIFO), append() vs pop(), etc.)
  Code Card           All code examples -- dark card on light background
  Callout Box         Definitions -- rounded rect, Cyan Electric border
  Exam Spotlight      PYQ slides -- large question centred on card
  3-Icon Grid         Key Takeaways -- 3 icons in equal columns
  Warning Banner      Common Mistakes -- red accent, alert icon

================================================
SECTION A1 -- LAYOUT SAFETY & OVERLAP PREVENTION
================================================

NON-NEGOTIABLE SAFE ZONE RULES:
  * Every slide must use a fixed 16:9 widescreen canvas.
  * Keep a minimum 0.35 inch margin from all slide edges.
  * No text box, badge, icon, card, or diagram may overlap another object.
  * Title area must be reserved separately from body area.
  * Body content must start only after the title area ends.

TITLE SAFE AREA:
  * Slide title box position: top 0.35 inch to 1.15 inch only.
  * No badge, icon, card, or body text may enter this title zone.
  * If title is long, wrap into maximum 2 lines.
  * Never allow title text to touch badges or cards.

BADGE PLACEMENT RULE:
  * Badges such as "Quick Recap", "PYQ", "1M", "60 seconds" must be placed
    in a fixed safe badge zone.
  * Badge zone: top-right corner, x >= 10.0 inch, y between 0.35 and 0.85 inch.
  * Badge must never be placed near the centre title area.
  * Badge text must stay inside the badge shape with 0.08 inch internal padding.

BODY SAFE AREA:
  * Body content must begin at y >= 1.45 inch on every content slide.
  * Large cards/callouts must begin at y >= 1.55 inch.
  * Bottom footer/caption area starts at y >= 6.85 inch.
  * Do not place main content in the footer zone.

TEXT FITTING RULE:
  * Do NOT shrink font below the required size.
  * If content does not fit, split into a continuation slide.
  * Use "(contd...)" in the title for continuation slides.
  * Never use PowerPoint auto-fit that reduces font size.
  * Never compress line spacing below 1.05.

OBJECT COLLISION CHECK -- before finalising each slide, verify:
  [ ] Title does not overlap badge.
  [ ] Badge does not overlap title or body.
  [ ] Body text does not overlap cards or icons.
  [ ] Code card has enough internal padding.
  [ ] No object is outside slide boundary.
  [ ] All text is fully visible after rendering.

RENDER QUALITY CHECK:
  After creating the PPT, render every slide as an image and inspect all
  rendered slides visually. If any slide has overlapping, clipped, hidden, or
  tiny text: fix the layout, split the slide if needed, render again, and only
  then provide the final PPT.

STRICT FAILURE RULE:
  A slide with overlapping text, clipped title, hidden badge, or unreadable
  content is considered FAILED and must be rebuilt before delivery.

================================================
SECTION B -- CONTENT SPECIFICATION
================================================

Topic     : Stack concept and operations using list PYQ part 2
Lecture   : #42 | Target duration: 35 min | Board: CBSE
Chapter   : Computational Thinking and Programming – 2
Class     : XII CS | Subject: Computer Science
Audience  : Class XII, CBSE Board, average to above-average students preparing for board exams

STRICT RULE: Every slide must be about "Stack concept and operations using list PYQ part 2" ONLY.

GENERATED STUDY NOTES HTML INPUT (OPTIONAL BUT PREFERRED):
  If the user provides/pastes the generated HTML study notes file for this lecture,
  treat that HTML as the AUTHORITATIVE PYQ practice source for the deck.
  Summarise all concepts into slide-friendly recap bullets, examples, diagrams,
  tables, and speaker notes without copying long HTML paragraphs verbatim.
  Quick Recap and exam-trap slides may be summarised from the HTML.
  PYQ Practice slides must follow Section F's PYQ Practice Question Rule.

DECK GOAL: This is a PRACTICE & APPLICATION session — students already
learned "Stack concept and operations using list" in an earlier lecture. Do NOT re-teach the theory from
scratch and do NOT reproduce that lecture's theory/worked-example slides.
Open with ONE quick recap slide per subtopic (definition restated in one
line + one example, nothing more), then spend the MAJORITY of the deck on
INTENSIVE MIXED DRILLING: as many real previous-year questions as exist for
this topic, mixed difficulty, timed rounds, peer-marking, and a heavier
Common Mistakes / exam-strategy emphasis. Cover every concept the PYQ
pattern bank names — drop none to save slides.

SLIDE COUNT -- DETERMINE BY CONTENT, NOT A FIXED NUMBER:
  Do not compress or stretch the topic to hit a fixed slide count.
  For a single-concept PYQ Practice deck, typical deck size is 10-14 slides.
  For multi-concept PYQ Practice decks, typical deck size is 15-24 slides.
  The actual count depends on source PYQ count, unique traps, answer slides, and practice flow.
  Never stretch a small PYQ pool only to reach a large slide count.
  Never cram multiple PYQ answers into unreadable slides by shrinking fonts or overcrowding.
    * Every subtopic listed in Section D gets EXACTLY 1 recap slide — no
      worked-example or theory-elaboration slides; that already happened in
      the teaching lecture. The bulk of the deck is PYQ/mixed-practice slides.
    * CRITICAL/HIGH/MEDIUM priority (Section F) only changes drilling ORDER
      (critical concepts drilled first), not slide count — recap stays
      minimal regardless of priority.
    * CONTINUATION (encouraged — do NOT cram): when one concept needs more room
      than a single slide allows (more than 3 bullets, or theory + worked example
      + an exam trap), SPLIT it across consecutive slides. Title the overflow slide
      "<SAME TOPIC> (contd...)" and add a small "...continue ->" marker bottom-right
      of the first slide so the flow is obvious. Two clean slides always beat one
      crowded slide — never shrink the font or exceed 3 bullets just to make it fit.
  Fixed-position slides (always present, regardless of total count):
    Title, Agenda, Quick Recap        -- start of deck
    Common Mistakes                         -- immediately after content slides
    PYQ Practice block: use EXACTLY 13 actual PYQs from the source pool. First create 1-2 question-only slide(s); then create one answer/explanation slide per question. So this block normally contains 14-15 slides -- after Common Mistakes
    Key Takeaways, Exit Ticket              -- final two slides, in that order


RECAP CLARITY (the only "explain" rule that applies here):
  Students already learned this in an earlier lecture — the Quick Recap slide(s)
  only need to JOG memory, not re-teach from zero:
    * One line plain-English restatement ("In simple words: ...") + ONE tiny
      example — never a full derivation or multi-step explanation.
    * If the recap risks reviving a known confusion (e.g. push vs pop, top vs bottom),
      a single Two Column reminder slide is fine — but do not expand it into a
      full theory lesson; that belongs in the original teaching lecture, not here.

================================================
SECTION C -- SLIDE OUTPUT FORMAT (USE EXACTLY)
================================================

+=======================================================+
SLIDE [n]: [SLIDE TITLE IN CAPS]
Layout     : [Full-bleed Dark / Left Icon+Text / Two Column /
              Code Card / Callout Box / Exam Spotlight /
              3-Icon Grid / Warning Banner]
Background : [#0D1B2A or #F0F4F8]
Title font : Montserrat Bold -- 44 pt on body slides / 54 pt on the Title slide
Body font  : Calibri 28 pt Regular
-------------------------------------------------------
VISUAL ELEMENT: [icon/shape/code card/diagram on this slide]

[Bullet 1 -- max 10 words]  (blue circle = definition)
[Bullet 2 -- max 10 words]  (green circle = tip)
[Bullet 3 -- max 10 words]  (red circle = warning)

CODE SLIDES -- paste inside dark card (list as stack):
  +------------------------------------------+
  |  stack = []                              |
  |  stack.append(10)     # push             |
  |  stack.append(20)     # push             |
  |  print(stack.pop())   # 20  (pop top)    |
  |  print(stack[-1])     # 10  (peek)       |
  +------------------------------------------+
  OUTPUT: 20
          10

DIAGRAM SLIDES: describe shapes, arrows, labels, layout
-------------------------------------------------------
SPEAKER NOTES: [2-3 sentences for teacher -- NOT on slide.
Real-life analogy / Did You Know fact / exam tip / story.
EXCEPTION -- on Exit Ticket slides the notes carry the COMPLETE answer + explanation; PYQ Practice answer slides instead show the full solution + explanation + Critical Trap directly ON the slide (never in notes) (code may span many lines).]
+=======================================================+

================================================
SECTION D -- MANDATORY SLIDE SPECIFICATIONS
================================================

TITLE SLIDE (slide 1)
  Layout     : Full-bleed Dark (#0D1B2A background)
  Topic name : "Stack concept and operations using list PYQ part 2" -- 54 pt Bold Cyan Electric (#00D4FF)
  Sub-line 1 : "XII CS Computer Science" -- 32 pt White
  Sub-line 2 : "CBSE Board | Lecture 42" -- 24 pt Slate Mist (#C9D4E0)
  Motif      : semi-transparent { } bracket centred background (15% opacity)

AGENDA (slide 2)
  Layout     : Left Icon+Text
  One row per subtopic below: icon-circle + subtopic name + time estimate

QUICK RECAP (right after Agenda — see recap slide cap in Section B)
  Layout     : Callout Box centred
  ONE line definition restated + ONE tiny example — no elaboration, no
  "explain for understanding" multi-slide treatment (already taught earlier)
  Badge      : "Quick Recap" top-right
  LAYOUT EXEMPTION: consecutive Quick Recap slides MAY all use Callout Box —
  the "no two consecutive same layout" rule (Sections A & G) does NOT apply
  within the recap run. Distinguish them by accent colour / icon instead.

CONTENT SLIDES (as many as the SLIDE COUNT rules in Section B require)
  Subtopics to cover (allocate slide count by PYQ FOCUS priority in Section F):
  • Stack concept and operations using list

  This is a PRACTICE deck: do NOT add theory/worked-example slides beyond the
  Quick Recap slides above. After the recap, go straight into MIXED PRACTICE —
  additional Exam Spotlight / Code Card slides drilling the actual PYQs from
  Section F only. Do not add extra exam-style questions unless the user explicitly
  requests more practice.

COMMON MISTAKES & EXAMINER TRAPS (right after all content slides)
  Layout     : Warning Banner
  Accent     : left thick border #E74C3C (4 pt) on each bullet card
  Title      : "DON'T MAKE THESE MISTAKES" -- 44 pt Bold Red
  EXACTLY 3 bullets -- specific PYQ traps with red alert icon

PYQ PRACTICE -- THIS IS A PYQ LECTURE: focus this block on PYQ only,
in two strict steps (13 questions total):

  STEP 1 -- QUESTION-ONLY SLIDE(S) (EXACTLY 1-2 slides, Exam Spotlight layout):
    Show ONLY question text (32 pt) + marks badge (Ocean Blue) + real year badge.
    This small pool uses every actual PYQ; do not create substitute or compressed questions.
    NO answer, NO explanation, NO trap anywhere on these slides.
    Batch multiple questions per slide (stacked Exam Spotlight cards) so this
    opening block stays at 1-2 slides regardless of the 13 total questions.
    Order      : Easy -> Medium -> Hard; within each difficulty, 1M -> 2M -> 3M -> higher
               (see PYQ PRACTICE QUESTION RULE in Section F)

  STEP 2 -- ANSWER SLIDES (one dedicated slide per question, SAME order as Step 1):
    Show ON THE SLIDE itself (never hidden in speaker notes):
      * The full model answer / worked solution
      * A one-line explanation of WHY (the reasoning, not just the final answer)
      * A "Critical Trap" callout (Warning Banner / Alert Red) -- the specific
        examiner trap or common mistake tied to THIS exact question
    Layout     : Exam Spotlight for short answers, Code Card for code-based answers
  Placement  : after Common Mistakes and before Key Takeaways

KEY TAKEAWAYS (second-to-last slide)
  Layout     : 3-Icon Grid (dark #0D1B2A background -- matches title)
  3 equal columns: large icon + 1-line heading (28 pt Bold) + 1-line summary (24 pt)
  EXACTLY 3 takeaways

EXIT TICKET (last slide)
  Layout     : Callout Box centred
  EXACTLY 1 MCQ or fill-in-the-blank -- question 32 pt, options 28 pt
  Timer badge: "60 seconds" top-right (Cyan Electric)
  ANSWER + EXPLANATION ONLY IN SPEAKER NOTES

================================================
SECTION E -- ENGAGEMENT RULES (MIN 2 IN SPEAKER NOTES)
================================================

1. Quick Recap slide: real-life analogy -- NOT textbook language
2. One slide: "Did You Know?" fun fact in speaker notes
3. One code slide: "Guess the Output?" -- ask class before revealing
4. Colour-coded bullets: red = warning, green = tip/example, blue = definition
5. Common Mistakes slide: one "Examiner Trap" with specific wrong answer students typically write

================================================
SECTION F -- PYQ FOCUS (WEIGHT SLIDES BY EXAM IMPORTANCE)
================================================

Board exam appearances: 13 times (2024-2026) | Total marks tested: 45M

DECK INTENT: build this as the POLISHED, EXAM-FOCUSED version of the study
notes — cover EVERY examiner-tested concept below (not just definitions),
and lead with the CRITICAL + CONFUSING concepts, giving them the most slide time.

TOP PRIORITY -- CRITICAL & CONFUSING CONCEPTS (open the content with these):
  ! Stack concept and operations using list — asked as Output Prediction/Programming/Short Answer; at 3,5M; 13x repeated --> own recap focus + PYQ drill priority; if it has a look-alike, use a Two-Column 'X vs Y' compare slide.

SUBTOPIC PRIORITY (allocate slide count by this ranking — see SLIDE COUNT rules in Section B):
  CRITICAL --> quick recap first, then highest-priority PYQ drill first
    * Stack concept and operations using list — 13x in exams, 45M total (years: 2026, 2025, 2024)

===========================================
QUESTION PATTERN BANK (What the board actually asks for THIS topic)
===========================================
Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: Stack concept and operations using list
  Pattern: Output Prediction=1, Programming=6, Short Answer=6 | Marks: 3M=10, 5M=3 | Total: 13 questions
  [Short Answer] [3M] [Medium] × 4
    → Core concept of Stack concept and operations using list
  [Programming] [3M] [Medium] × 3
    → Core concept of Stack concept and operations using list
  [Programming] [5M] [Hard] × 2
    → Output/result interpretation for the current concept
  [Short Answer] [5M] [Hard]
    → Core concept of Stack concept and operations using list
  [Programming] [3M] [Medium]
    → Output/result interpretation for the current concept
  [Short Answer] [3M] [Medium]
    → Output/result interpretation for the current concept
  [Output Prediction] [3M] [Medium]
    → Output/result interpretation for the current concept


===========================================
IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
===========================================
| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | Stack concept and operations using list | 115 | 13 | 45M | 2026, 2025, 2024 | CRITICAL |

EXAMINER FINGERPRINT -- TRAPS TO COVER INTERNALLY

Use this section only for internal slide planning. Do not print this
heading or these internal labels on slides.

For this lecture, the deck must strongly cover these traps:

No static trap list exists yet for "Stack concept and operations using list". Self-generate 4–7 traps from:
- actual question patterns for Stack concept and operations using list
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

* Common Mistakes slide must select the top 3 traps from this Examiner
  Fingerprint list.
* PYQ Practice slides must together cover at least 4 traps from the Examiner Fingerprint list.
* Content slides must teach the traps before practice slides test them.

ACTUAL PYQ SET FOR PRACTICE
  Source pool has 13 PYQs.
  Since the pool has 15 or fewer questions, use all 13 actual PYQs.
  Do not replace these with newly framed representative questions.
  Do not compress by dropping, replacing, paraphrasing, or hiding actual PYQs.
  All 13 actual PYQs must appear visibly in the question-only block.
  Grouping related answers on the same answer/explanation slide is allowed only
  for layout efficiency, provided every PYQ still gets:
    - final answer
    - one-line explanation
    - marking point
    - Critical Trap
  Order questions Easy -> Tough; within difficulty, order 1M -> 2M -> 3M -> 4/5M.
  Every PYQ must be visibly accounted for in the question-only block
  and in grouped answer/explanation coverage by concept pattern.
  Each PYQ needs a final answer, one-line explanation, marking point,
  and Critical Trap directly on an answer/explanation slide.
  Do not create substitute or compressed questions for this small source pool.

  Pattern 1. [3M] [Medium/Short Answer] Concept: Stack concept and operations using list | source example: 2024
  ```
  A) You have a stack named BooksStack that contains records of books. Each book record is represented as a list containing book_title, author_name, and publication_year.
  Write the following user-defined functions in Python to perform the specified operations on the stack BooksStack:
  (I) push_book(BooksStack, new_book): This function takes the stack BooksStack and a new book record new_book as arguments and pushes the new book record onto the stack.
  (II) pop_book(BooksStack): This function pops the topmost book record from the stack and returns it. If the stack is already empty, the function should display "Underflow".
  (III) peep(BookStack): This function displays the topmost element of the stack without deleting it. If the stack is empty, the function should display 'None'.
  ```
  Pattern 2. [3M] [Medium/Programming] Concept: Stack concept and operations using list | source example: 2024
  ```
  B) Write the definition of a user-defined function push_even(N) which accepts a list of integers in a parameter N and pushes all those integers which are even from the list N into a Stack named EvenNumbers.
  Write function pop_even() to pop the topmost number from the stack and returns it. If the stack is already empty, the function should display "Empty".
  Write function Disp_even() to display all elements of the stack without deleting them. If the stack is empty, the function should display 'None'.
  For example:
  If the integers input into the list VALUES are: [10, 5, 8, 3, 12]
  Then the stack EvenNumbers should store: [10, 8, 12]
  ```
  Pattern 3. [5M] [Hard/Programming] Concept: Stack concept and operations using list | source example: 2024
  ```
  A list contains the details of Employees working in an organization. Write the following user defined functions in Python to perform the given operations:
  (i) Push_Employee(EmpList) : To push the details of the employees into the stack EmpStack who are working in Admin department.
  (ii) Pop_Employee() : To pop the elements from the stack and display. Also display "Empty" when there are no elements in the stack.
  
  For example:
  If the list contains the details as:
  ['EMP01','Raj','Admin']
  ['EMP02','Shreya','HR']
  ['EMP03','Rohan','Admin']
  ['EMP04','Anita','Admin']
  ['EMP05','Priya','HR']
  
  The output should be:
  Anita
  Rohan
  Empty
  ```
  Pattern 4. [5M] [Hard/Short Answer] Concept: Stack concept and operations using list | source example: 2024
  ```
  Write the following Python functions:
  (i) push_record(): To push the product details of the products whose price is more than 500 into the stack Record.
  
  (ii) pop_record(): To pop the elements from the stack and display. Also display "No Record" when there are no elements in the stack.
  ```
  Pattern 5. [3M] [Medium/Programming] Concept: Stack concept and operations using list | source example: 2025
  ```
  Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all elements which contain the substring 'books' (case insensitive) onto the list SBOOKS.
  ```
  Pattern 6. [3M] [Medium/Programming] Concept: Stack concept and operations using list | source example: 2025
  ```
  Write a user defined function in Python Push() which takes a list named DATA as an argument and pushes all even numbers in the list on to the list EVENLIST.
  ```
  Pattern 7. [3M] [Medium/Short Answer] Concept: Stack concept and operations using list | source example: 2025
  ```
  (a) A stack named KeyStack contains records of some computer keyboards. Each record is represented as a list containing Make, Keys, Connectivity. The Make and Connectivity are strings, and Keys is an integer. For example, a record in the stack may be ('Hitech', 105, 'USB').
  Write the following user-defined functions in Python to perform the specified operations on KeyStack :
  (I) push_key(KeyStack, new_key) : This function takes the stack KeyStack and a new record as arguments new_key and pushes this new record onto the stack.
  (II) pop_key(KeyStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow".
  (III) isEmpty(KeyStack) : This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.
  
  (II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
  (III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.
  ```
  Pattern 8. [3M] [Medium/Short Answer] Concept: Stack concept and operations using list | source example: 2025
  ```
  (b) Write the following user-defined functions in Python :
  (I) push_vowels(S,St) : Here S is a string and St is a list representing a stack. The function should push all the vowels of the string S onto the stack St. For example, if the string S is "Easy Concepts", then the function push_vowels() should push the elements 'E','a','o','e' onto the stack.
  
  (II) pop_one(St) : The function should pop an element from the stack St, and return this element. If the stack is empty, then the function should display the message 'Stack Underflow', and return None.
  (III) display_all(St) : The function should display all the elements of the stack St, without deleting them. If the stack is empty, the function should display the message 'Empty Stack'.
  ```
  Pattern 9. [3M] [Medium/Programming] Concept: Stack concept and operations using list | source example: 2025
  ```
  A list containing records of products as
  L = [("Laptop", 90000), ("Mobile", 30000), ("Pen", 50), ("Headphones", 1500)]
  Write the following user-defined functions to perform operations on a stack named Product to:
  I. Push_element() – To push an item containing the product name and price of products costing more than 50 into the stack.
  Output: [('Laptop', 90000), ('Mobile', 30000), ('Headphones', 1500)]
  II. Pop_element() – To pop the items from the stack and display them. Also, display "Stack Empty" when there are no elements in the stack.
  Output:
  ('Headphones', 1500)
  ('Mobile', 30000)
  ('Laptop', 90000)
  Stack Empty
  ```
  Pattern 10. [5M] [Hard/Programming] Concept: Stack concept and operations using list | source example: 2025
  ```
  A list contains the names of boys who participated in an inter school level swimming competition. Write the following user defined functions in Python to perform given operations:
  (i) Push_element(Boys) : To push the names of boys in the stack where the length of the name is more than 5 characters.
  (ii) Pop_element() : To pop the elements from the stack and display them. Also display "Stack Empty" when there are no elements in the stack.
  
  For example:
  If the list of boys who participated in the competition is :
  ['Rohit', 'Rahul', 'Rishabh', 'Virat', 'Hardik']
  The stack should contain
  ['Rishabh', 'Hardik']
  The output should be displayed as:
  Hardik
  Rishabh
  Stack Empty
  ```
  Pattern 11. [3M] [Medium/Short Answer] Concept: Stack concept and operations using list | source example: 2026
  ```
  (a) A stack named FruitStack, implemented using list, contains records of some fruits. Each record is represented as a dictionary with keys 'Name', 'Origin', 'Price', and 'Expiry'.
  A sample record is given here :
  {'Name':'Apple', 'Origin':'France', 'Price':120, 'Expiry':'12-08-2025'}
  Write the following user-defined functions in Python to perform the specified operations on FruitStack :
  (i) push_fruit(FruitStack, Fruit): This function takes the stack FruitStack and a new record Fruit as arguments and pushes the record stored in Fruit onto FruitStack if the Price is less than 100.
  (ii) pop_fruit(FruitStack) : This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display "UNDERFLOW".
  (iii) display(FruitStack) : This function displays all the elements of the stack starting from the topmost element. If the stack is empty, the function should display 'EMPTY STACK'.
  ```
  Pattern 12. [3M] [Medium/Short Answer] Concept: Stack concept and operations using list | source example: 2026
  ```
  (b) Write a Python program to accept 10 integers from the user. If the entered number is a three-digit even integer, push it onto a stack. After all inputs are taken, pop all the three-digit even integers from the stack and display them. For example, if the user enters 12, 31, 320, 457, 6, 92, 924, 220, 1, 218, then the stack should contain :
  320, 924, 220, 218
  and the output of the program should be :
  218 220 924 320
  ```
  Pattern 13. [3M] [Medium/Output Prediction] Concept: Stack concept and operations using list | source example: 2026
  ```
  (a) Write the output of the following code :
  def Exam2026(given) :
      new=[]
      for ch in given[1:-1]:
          if ch.isupper():
              new.reverse()
          elif ch not in new:
              new.append(ch)
          elif ch in new:
              new.pop()
      print(new)
  Exam2026("Gold-24Medals")
  ```

SLIDE WEIGHTING RULE:
  CONFUSING/CRITICAL concepts --> quick recap first, then highest-priority PYQ drill;
                                  use 'X vs Y' compare slide for look-alikes
  HIGH subtopics     --> own slide
  MEDIUM subtopics   --> 1 bullet max on a shared slide
  Every concept named in the QUESTION PATTERN BANK above MUST appear on a slide —
  a concept the board has actually tested may NEVER be dropped to save slides.

SOURCE POOL RULE:
  Because this source pool has only 13 PYQs, use all 13 actual PYQs.
  Do not drop, replace, paraphrase, or hide any actual PYQ.
  Every PYQ must appear visibly in the question-only block.
  Grouping related answers is allowed only for layout efficiency.
  Compression by omission is allowed only when source pool has more than 15 PYQs.
  If the pool has 15 or fewer PYQs, every actual PYQ must be included and accounted for.
  If a question is reproduced verbatim, show its real year and marks.
  Never fabricate a year, section, paper, or marks badge.

PYQ PRACTICE QUESTION RULE:
  Use EXACTLY 13 actual PYQs from the source pool.
  The authoritative count is the current source count (13), not a hardcoded number.
  If source PYQ count is 15 or fewer, use exactly the source count of actual PYQs.
  If source PYQ count is more than 15, fully discuss the highest-yield 15
  and compactly account for the rest.
  Create 1-2 question-only slide(s), then one answer/explanation slide per question.
  Order practice Easy -> Medium -> Hard; within each difficulty, order
  1M -> 2M -> 3M -> 4/5M.

  PYQ ANSWER VISIBILITY RULE:
  Question-only slides show only question text, real marks badge, and real year badge.
  Answer/explanation slides show the model answer, one-line explanation, and
  "Critical Trap" callout directly on the slide.

SMALL-POOL ACTUAL-QUESTION RULE:
  For this small source pool, use all actual PYQs with real year and marks.
  Do not create substitute, compressed, or newly framed questions.
  Never show fake year, fake section, or fake marks.

NO-FABRICATION RULE (board integrity -- never break this):
  Use EXACTLY 13 actual PYQs from the set above.
  Never fabricate a previous-year question, year, section, paper, or marks badge.

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SECTION G -- QUALITY CHECKLIST (VERIFY BEFORE OUTPUT)
================================================

Visual Checks:
  [ ] Title font >= 44 pt on every slide
  [ ] Body font >= 28 pt on every slide
  [ ] Code font >= 24 pt inside dark card only
  [ ] No font below 24 pt anywhere
  [ ] Every slide has icon, shape, code card, or diagram
  [ ] No unnecessary repeated layout; continuation, paired worked-example, and necessary code-tracing slides may repeat layout.
  [ ] Sandwich: dark Title -> light content -> dark Key Takeaways -> light Exit Ticket
  [ ] { } bracket motif on every content slide
  [ ] NO accent lines under titles
  [ ] NO full-width colour bars or stripes
  [ ] NO cream/beige backgrounds
  [ ] Bullets left-aligned (titles centred only)
  [ ] ONE clear focal point per slide (one hero element, one accent moment)
  [ ] Objects snapped to the grid -- tops/left edges aligned, nothing free-floating
  [ ] Accent colour <= 10% of slide area; cards use 6-8% tints, not saturated fills
  [ ] Every slide's visual carries meaning (no decorative icon-circles / clip-art)
  [ ] At least 60% of each content slide is background + breathing space

Content Checks:
  [ ] CRITICAL/HIGH subtopics in Section D have dedicated slides
  [ ] MEDIUM subtopics are covered on shared slides unless they have multiple
      distinct cases
  [ ] Multi-case subtopics (push, pop, peek, underflow) have EACH case
      covered, not compressed into one slide
  [ ] Every recap slide is a one-line restatement + one tiny example (no re-teaching)
  [ ] No slide has more than 3 bullets
  [ ] No bullet longer than 10 words
  [ ] Every code example on its own Code Card slide
  [ ] Common Mistakes slide has EXACTLY 3 examiner traps (red accent)
  [ ] Exactly 13 PYQ questions are used.
  [ ] Question-only and answer/explanation coverage is complete.
  [ ] No actual PYQ is silently dropped.
  [ ] Question-only slides show no answer, no explanation, and no trap.
  [ ] Answer slides show model answer + explanation + Critical Trap directly on slide.
  [ ] Key Takeaways slide has EXACTLY 3 takeaways in 3-Icon Grid layout
  [ ] Exit Ticket has 1 question with answer ONLY in speaker notes
  [ ] All speaker notes include teacher dialogue (EXCEPT PYQ Practice answer slides (answer is ON the slide, not in notes) & Exit Ticket (answer in notes) -- Section C)
  [ ] Minimum 2 engagement techniques across speaker notes

Layout Safety Checks:
  [ ] Every slide uses 16:9 widescreen canvas
  [ ] All objects keep at least 0.35 inch margin from slide edges
  [ ] Title stays within y=0.35-1.15 inch and wraps to max 2 lines
  [ ] Body starts at y >= 1.45 inch; large cards/callouts at y >= 1.55 inch
  [ ] Badges stay in the top-right badge zone and never touch title/body
  [ ] No text, badge, icon, card, code block, or diagram overlaps another object
  [ ] No PowerPoint auto-fit has reduced required font sizes
  [ ] Continuation slides are used whenever content would otherwise crowd
  [ ] Rendered slide images have no clipped, hidden, overlapping, or tiny text

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