IB Computer Science Topic B2.2.3 Concept of a Stack as a "last In, First Out" (LIFO) Data Structure Revision Notes (SL/HL)

IB Computer Science Topic B2.2.3 Concept of a Stack as a "last In, First Out" (LIFO) Data Structure Revision Notes (SL/HL) | RevisionDojo

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Understanding Stacks as LIFO Data Structures

A stack is a linear data structure that follows the Last In, First Out (LIFO) principle.

The last item added is the first one removed.
Analogy: Like a stack of plates in a cafeteria—you can only add/remove the plate at the top.

Hint

Always think “last added = first out.”

Common Mistake

Assuming you can directly access elements in the middle (not possible without popping).

Fundamental Stack Operations

Push
1. Adds an item to the top of the stack.
2. Time Complexity: O(1)
Pop
1. Removes and returns the item from the top.
2. Time Complexity: O(1)
Peek / Top

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Understanding Stacks as LIFO Data Structures

A stack is a linear data structure that follows the Last In, First Out (LIFO) principle.

The last item added is the first one removed.
Analogy: Like a stack of plates in a cafeteria—you can only add/remove the plate at the top.

Hint

Always think “last added = first out.”

Common Mistake

Assuming you can directly access elements in the middle (not possible without popping).

Fundamental Stack Operations

Push
1. Adds an item to the top of the stack.
2. Time Complexity: O(1)
Pop
1. Removes and returns the item from the top.
2. Time Complexity: O(1)
Peek / Top

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A1 Computer fundamentals4 subtopics

A2 Networks4 subtopics

A3 Databases4 subtopics

A4 Machine learning4 subtopics

B1 Computational thinking1 subtopic

B2 Programming5 subtopics

B3 Object-oriented programming2 subtopics

B4 Abstract data types (HL only)1 subtopic

IB Computer Science Topic B2.2.3: Concept of a Stack as a "last In, First Out" (LIFO) Data Structure Notes

A1 Computer fundamentals4 subtopics

A2 Networks4 subtopics

A3 Databases4 subtopics

A4 Machine learning4 subtopics

B1 Computational thinking1 subtopic

B2 Programming5 subtopics

B3 Object-oriented programming2 subtopics

B4 Abstract data types (HL only)1 subtopic

Understanding Stacks as LIFO Data Structures

Fundamental Stack Operations

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Understanding Stacks as LIFO Data Structures

Fundamental Stack Operations

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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