Pointers and Linked Lists Concepts
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Questions and Answers

Which operation is used to add a new node to a linked list?

  • Deletion
  • Insertion (correct)
  • Traversal
  • Dequeue

Inserting a node at the last position in a linked list involves pointing the last node's next pointer to the new node.

True (A)

What are the three types of insertion in a linked list?

Inserting at first, inserting at last, inserting at mid

In the function insertFirst, if the head is NULL, the new node becomes the ______.

<p>head</p> Signup and view all the answers

Match the types of insertion with their descriptions:

<p>Inserting at first = Adds a node before the current head Inserting at last = Adds a node after the current last node Inserting at mid = Adds a node between two existing nodes</p> Signup and view all the answers

What happens if the position specified for deletion is greater than the size of the linked list?

<p>The function does nothing (C)</p> Signup and view all the answers

The search function will return the position of the value if it is not found in the linked list.

<p>False (B)</p> Signup and view all the answers

In which scenario does a linked list facilitate adding new contacts in a phonebook?

<p>When names need to be sorted in ascending order.</p> Signup and view all the answers

To delete a node from a linked list, we must first access the ______ node.

<p>previous</p> Signup and view all the answers

Match each application of linked lists with its appropriate description:

<p>Web-browser = Creates linked history for navigation Image viewer = Displays a sequence of images Phonebook = Stores contact names in order Search function = Locates a value in the list</p> Signup and view all the answers

What happens if the head of the list is NULL when inserting a node at the end?

<p>The node becomes the head of the list. (A)</p> Signup and view all the answers

The insertAtPos function allows insertion at any position in the linked list.

<p>True (A)</p> Signup and view all the answers

What is the purpose of the 'prev' pointer in the insertion at position operation?

<p>To point to the node before the insertion position.</p> Signup and view all the answers

In the deletion process, we update the next pointer of the previous node to point to the ______ node of the target node.

<p>next</p> Signup and view all the answers

Match the following operations with their descriptions:

<p>insertLast = Adds a node at the end of the list insertAtPos = Inserts a node at a specific position deleteNode = Removes a node from the list insertFirst = Adds a node at the beginning of the list</p> Signup and view all the answers

What happens in the insertAtPos function if the position specified is greater than the current size of the list?

<p>The node is added at the end. (C)</p> Signup and view all the answers

The next pointer of the new node remains NULL after it is inserted at the end.

<p>False (B)</p> Signup and view all the answers

What is the first step in the deletion process in a linked list?

<p>Find the previous and next nodes of the target node.</p> Signup and view all the answers

What does the enqueue function do in the provided code?

<p>Adds a new element to the back of the queue (A)</p> Signup and view all the answers

The dequeue function will always return the last element added to the queue.

<p>False (B)</p> Signup and view all the answers

What happens to the rear pointer when the queue becomes empty after a dequeue operation?

<p>The rear pointer becomes NULL.</p> Signup and view all the answers

In the peek function, the value returned is the ______ of the front node.

<p>data</p> Signup and view all the answers

Match each function with its purpose:

<p>enqueue = Add an element to the queue dequeue = Remove an element from the front peek = View the front element printQueue = Display all elements in the queue</p> Signup and view all the answers

What is the primary purpose of the 'enqueue' function in the provided code?

<p>To add a new node to the rear of the queue (A)</p> Signup and view all the answers

The 'peek' function returns the data of the rear node of the queue.

<p>False (B)</p> Signup and view all the answers

In the 'dequeue' function, if the front pointer becomes NULL, the ______ pointer should also be set to NULL.

<p>rear</p> Signup and view all the answers

Match the functions with their respective purposes:

<p>enqueue = Adds a new element to the queue dequeue = Removes and returns the front element peek = Returns the front element without removing it printQueue = Displays all elements in the queue</p> Signup and view all the answers

What is the first action taken when the reading symbol is an operand?

<p>Directly print it to the result (B)</p> Signup and view all the answers

A right parenthesis ')' is pushed onto the stack during infix to postfix conversion.

<p>False (B)</p> Signup and view all the answers

What should be done when a left parenthesis '(' is encountered?

<p>Push it into the stack</p> Signup and view all the answers

When an operator is read, if it has ______ precedence than the top of the stack's operator, pop the stack.

<p>higher or equal</p> Signup and view all the answers

Match the following symbols with their corresponding actions:

<p>Operand = Print directly Left Parenthesis = Push onto the stack Right Parenthesis = Pop until left parenthesis Operator = Push after checking precedence</p> Signup and view all the answers

What does the 'pop' operation do in a stack?

<p>Removes the element from the top of the stack (B)</p> Signup and view all the answers

In the expression (A+B)*(C-D), what is the resultant postfix notation?

<p>A B + C D - * (C)</p> Signup and view all the answers

During the conversion process, numbers must always be popped from the stack before they can be printed.

<p>False (B)</p> Signup and view all the answers

Items in a stack are removed in the order they were inserted.

<p>False (B)</p> Signup and view all the answers

What is the purpose of the 'push' operation in a stack?

<p>To add an element to the top of the stack.</p> Signup and view all the answers

What happens when a right parenthesis ')' is encountered in the conversion process?

<p>Pop from the stack until the corresponding left parenthesis is found.</p> Signup and view all the answers

In a stack, if the top is set to -1, it indicates that the stack is ______.

<p>empty</p> Signup and view all the answers

In the expression 10 + 2 * 8 - 3, the first action is to output the number ______.

<p>10</p> Signup and view all the answers

Match the stack operations with their descriptions:

<p>push = Adds an element to the top of the stack pop = Removes an element from the top of the stack peek = Retrieves the top element without removing it isEmpty = Checks if the stack has any elements</p> Signup and view all the answers

When processing the expression 10 + 2 * 8 - 3, what happens after encountering the second operator '*', given that + is on the stack?

<p>Push * onto the stack (A)</p> Signup and view all the answers

Which of the following correctly describes the Last-In, First-Out (LIFO) principle?

<p>The last element added is the first one to be removed. (C)</p> Signup and view all the answers

A stack can be implemented using a linked list only.

<p>False (B)</p> Signup and view all the answers

What happens to the 'top' variable when an element is pushed onto a stack?

<p>It is incremented by 1.</p> Signup and view all the answers

The function used to return the element at the top of the stack without removing it is called ______.

<p>peek</p> Signup and view all the answers

What is the primary role of the 'size' operation in a stack?

<p>To determine the number of elements in the stack (D)</p> Signup and view all the answers

Which operation removes the top element from a stack implemented using a linked list?

<p>Pop (A)</p> Signup and view all the answers

The push operation adds an element to the end of the linked list.

<p>False (B)</p> Signup and view all the answers

What data structure is used to implement a stack as described?

<p>Linked list</p> Signup and view all the answers

To reverse a string using a stack, we push each character into the stack and then ______ them.

<p>pop</p> Signup and view all the answers

Match the stack operation with its description:

<p>Push = Inserts an element at the beginning of the stack Pop = Removes the top element of the stack Top = Accesses the top element without removing it IsEmpty = Checks if the stack has no elements</p> Signup and view all the answers

What is the main application of a stack in browsers?

<p>To keep track of visited pages (D)</p> Signup and view all the answers

The top of a stack implemented with a linked list is always NULL when it is empty.

<p>True (A)</p> Signup and view all the answers

In the context of stack operations, what does 'top' refer to?

<p>The top element of the stack</p> Signup and view all the answers

When an element is popped from the stack, the top pointer moves to the ______ element.

<p>next</p> Signup and view all the answers

Which of the following actions is not an application of stacks?

<p>Algorithm sorting (D)</p> Signup and view all the answers

What is the final result after evaluating the postfix expression 7 4 -3 * 1 5 + / *?

<p>-14 (D)</p> Signup and view all the answers

Postfix notation requires parentheses to indicate the order of operations.

<p>False (B)</p> Signup and view all the answers

What is the purpose of the stack in evaluating a postfix expression?

<p>To store operands during the evaluation process.</p> Signup and view all the answers

When the expression evaluation is complete, the number in the stack is the ______ answer.

<p>final</p> Signup and view all the answers

Match the following operations with their results after evaluating the expression:

<p>7 4 - = 3 4 * -3 = -12 1 5 + = 6 -12 / 6 = -2</p> Signup and view all the answers

In the postfix expression evaluation process, what happens if the element is an operator?

<p>Pop operands from the stack and push the result back. (C)</p> Signup and view all the answers

To convert an infix expression to postfix, numbers are outputted immediately as they are scanned.

<p>True (A)</p> Signup and view all the answers

How do you begin evaluating a postfix expression?

<p>By creating a stack to store operands.</p> Signup and view all the answers

When the postfix expression is completely evaluated, the ______ in the stack represents the final result.

<p>last number</p> Signup and view all the answers

Match the postfix expression with its corresponding evaluation steps:

<p>7 4 -3 * = Multiply the first two popped values then subtract 1 5 + / = Add the last two popped values and then divide 4 * -3 = Multiply 4 by -3</p> Signup and view all the answers

What does the 'peek' operation in a stack do?

<p>Retrieves the top element without removing it (C)</p> Signup and view all the answers

In a stack, the Last-In, First-Out (LIFO) principle means that the first element added is the first element removed.

<p>False (B)</p> Signup and view all the answers

What happens when you call the 'pop' operation on a stack?

<p>It removes the top element from the stack.</p> Signup and view all the answers

In stack implementations using arrays, the variable 'top' indicates the ______ element of the stack.

<p>index of the top</p> Signup and view all the answers

Match the following stack operations with their descriptions:

<p>push = Adds an element to the top of the stack pop = Removes the top element from the stack isEmpty = Checks if the stack has any elements size = Returns the number of elements in the stack</p> Signup and view all the answers

Which operation would you use to check if a stack is empty?

<p>isEmpty (A)</p> Signup and view all the answers

It is possible to add elements to both ends of a stack.

<p>False (B)</p> Signup and view all the answers

What is the consequence of attempting to pop an element from an empty stack?

<p>It can lead to an underflow error.</p> Signup and view all the answers

Which of the following operations removes the top element from a stack?

<p>Pop (B)</p> Signup and view all the answers

In a stack implementation using a linked list, the top pointer points to the last element added to the stack.

<p>False (B)</p> Signup and view all the answers

What does the push operation do in a stack implemented with a linked list?

<p>Inserts a new element at the top of the stack.</p> Signup and view all the answers

The stack operation that adds an element at the beginning of the list is called ______.

<p>push</p> Signup and view all the answers

Match the following stack operations with their corresponding descriptions:

<p>Push = Removes the top element Pop = Adds a new element to the top Peek = Returns the top element without removing it IsEmpty = Checks if the stack is empty</p> Signup and view all the answers

What is one application of stacks?

<p>Reversing a string (B)</p> Signup and view all the answers

In a linked list stack, if the top is NULL, the stack is considered empty.

<p>True (A)</p> Signup and view all the answers

In the context of reversing a string using a stack, what is the order of operations?

<p>Push characters onto the stack then pop them to retrieve in reverse order.</p> Signup and view all the answers

What action is taken when a right parenthesis ')' is encountered during infix to postfix conversion?

<p>Pop operators from the stack until the left parenthesis is popped. (A)</p> Signup and view all the answers

An operator is pushed onto the stack without checking its precedence first.

<p>False (B)</p> Signup and view all the answers

Which notation is used to express the resultant of the expression (A+B)*(C-D)?

<p>A B + C D - *</p> Signup and view all the answers

In the expression 10 + 2 * 8 - 3, the first output is the number _____ .

<p>10</p> Signup and view all the answers

What happens when an operator with higher precedence than the stack's top operator is read?

<p>The operator is pushed onto the stack. (C)</p> Signup and view all the answers

An operand is printed immediately upon being read.

<p>True (A)</p> Signup and view all the answers

What is the purpose of popping the stack when encountering an operator?

<p>To ensure correct output order based on operator precedence.</p> Signup and view all the answers

What is the first step in evaluating a postfix expression?

<p>Create a stack to store operands and scan the expression. (C)</p> Signup and view all the answers

In a postfix expression, operands are evaluated right after being scanned.

<p>False (B)</p> Signup and view all the answers

What is the final output of evaluating the postfix expression '7 4 -3 * 1 5 + / *'?

<p>5</p> Signup and view all the answers

When the expression is ended, we pop all the ______ in the stack for the final output.

<p>operators</p> Signup and view all the answers

Match the following expressions with their evaluations:

<p>10 + 2 * 8 - 3 = 10 2 8 * + 3 - 7 4 -3 * 1 5 + / * = 5 3 + 4 * 2 = 3 4 2 * + 5 1 2 + 4 * + 3 - = 14</p> Signup and view all the answers

In postfix evaluation, operators are evaluated before operands are popped from the stack.

<p>False (B)</p> Signup and view all the answers

What remains on the stack after all operators are popped and the expression is ended?

<p>The final result of the expression</p> Signup and view all the answers

When processing the expression '10 + 2 * 8 - 3', the result after outputting '10 2 8 * +' is _____

<p>3</p> Signup and view all the answers

Match the following postfix expressions with their results:

<p>7 4 -3 * 1 5 + / * = -14 10 2 8 * + 3 - = 27 4 5 + 6 * = 54 6 2 3 + * = 30</p> Signup and view all the answers

What happens when a right parenthesis ')' is encountered during infix to postfix conversion?

<p>Pop from the stack until a left parenthesis is encountered (C)</p> Signup and view all the answers

The '+' operator has higher precedence than the '*' operator.

<p>False (B)</p> Signup and view all the answers

What is the resultant postfix of the expression (A + B) * (C - D)?

<p>A B + C D - *</p> Signup and view all the answers

When an operand is read during conversion, it is ______ to the result.

<p>printed</p> Signup and view all the answers

Match the following operators with their precedence levels (1 for lowest, 3 for highest):

<ul> <li>= 1</li> </ul> <ul> <li>= 3</li> </ul> <ul> <li>= 1 / = 3</li> </ul> Signup and view all the answers

In the expression 10 + 2 * 8 - 3, which number is outputted first?

<p>10 (B)</p> Signup and view all the answers

Operators are always pushed onto the stack without checking their precedence.

<p>False (B)</p> Signup and view all the answers

What does the algorithm do when it reads a left parenthesis '('?

<p>Push it onto the stack</p> Signup and view all the answers

What is the time complexity of the push operation in a stack implemented using a linked list?

<p>O(1) (A)</p> Signup and view all the answers

Popping an element from a stack removes the last element that was added to it.

<p>False (B)</p> Signup and view all the answers

What is the purpose of the 'top' pointer in stack implementation using a linked list?

<p>To point to the top node of the stack.</p> Signup and view all the answers

During the push operation, if the stack is empty (top is ______), the new node becomes the top of the stack.

<p>NULL</p> Signup and view all the answers

Match the stack operations with their respective descriptions:

<p>Push = Adds an element to the top of the stack Pop = Removes the top element from the stack Peek = Returns the top element without removing it IsEmpty = Checks if the stack is empty</p> Signup and view all the answers

Which of the following is a common application of stacks?

<p>Reversing strings (A)</p> Signup and view all the answers

What is the result of popping elements from a stack that contains the elements 11, 22, and 33 (top to bottom)?

<p>33, 22, 11</p> Signup and view all the answers

Stacks can be used to track the pages visited in a web browser tab.

<p>True (A)</p> Signup and view all the answers

What is the primary function of the 'peek' operation in a stack?

<p>Retrieve the top element without removing it (A)</p> Signup and view all the answers

In a stack, the operation to remove an element is called 'push'.

<p>False (B)</p> Signup and view all the answers

What does the 'isEmpty' operation determine in a stack?

<p>It checks whether the stack is empty.</p> Signup and view all the answers

In a stack implemented using an array, if the stack is empty, the top is set to ______.

<p>-1</p> Signup and view all the answers

Match the stack operations with their correct descriptions:

<p>push = Adds an element to the top of the stack pop = Removes an element from the top of the stack size = Determines the number of elements in the stack peek = Examines the element at the top of the stack</p> Signup and view all the answers

Which statement describes the Last-In, First-Out (LIFO) principle?

<p>Items are removed in the reverse order of their addition (C)</p> Signup and view all the answers

In a stack implementation, the 'top' variable is always set to the size of the stack.

<p>False (B)</p> Signup and view all the answers

What occurs when an element is pushed onto a stack?

<p>The top index is incremented, and the element is added at that index.</p> Signup and view all the answers

Flashcards

Linked List Insertion

Adding a new node to a linked list at various positions (first, last, or middle).

Insertion at first (prepend)

Adding a new node to the beginning of a linked list.

Insertion at last (append)

Adding a new node to the end of a linked list.

Linked List Size

Counting the number of nodes in a linked list.

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Linked List Node

A data structure that stores data and a reference (pointer) to the next node to create a sequence of nodes.

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Linked List Deletion

Deleting a node at a specific position in a linked list. If position is 1, then delete the head. Otherwise, find the previous node and update links.

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Linked List Searching

Finding a node with a specific data value in a linked list. Starts at the beginning of the list and checks each node's data until a match is found or the end is reached.

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Linked List Head

The first node in a linked list.

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Uses of Linked Lists

Linked lists are used in various applications like web browsers, image viewers, and phonebooks.

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Linked List Position

A node's location in a linked list, often represented as an index, where the first node is position 1.

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Insert at Last

Adds a new node to the end of a linked list.

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Insert at Position

Adds a new node at a specific location within a linked list.

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Insertion, Position 1

Inserts a new node at the beginning of a linked list.

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Insertion, Last Position

Adds a new node at the end of a linked list.

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Deletion of Node

Removes a node from a linked list.

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Linked List

A data structure where elements are not stored contiguously, instead linked via pointers.

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Node

An element in a linked list that contains data and a pointer to the next node.

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Linked List Traversal

Process of visiting each node in the linked list sequentially.

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Queue Peek

Returns the data of the element at the front of the queue without removing it.

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Queue Enqueue

Adds a new element to the rear of the queue.

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Queue Dequeue

Removes and returns the element at the front of the queue.

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Queue Front

A pointer that points to the first element in the queue.

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Queue Rear

A pointer that points to the last element in the queue.

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Stack: LIFO

A data structure that follows the Last-In, First-Out (LIFO) principle, where the last element added is the first to be removed. Think of it as a stack of plates where you remove the top plate first.

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Stack: Operations

Stacks have basic operations like push, pop, peek, isEmpty, and size. Push adds an element to the top, pop removes the top element, peek retrieves the top element, isEmpty checks if the stack is empty, and size gives the number of elements in the stack.

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Stack: Push

The operation to add an element to the top of the stack. Think of placing a new plate on the top of your stack of plates.

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Stack: Pop

The operation to remove an element from the top of the stack. Think of removing the top plate from your stack of plates.

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Stack: Peek

The operation to retrieve the top element of the stack without removing it. Think of looking at the top plate in your stack of plates without taking it out.

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Stack: isEmpty

Checks if the stack is empty. This tells you if there are any elements in the stack or not.

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Stack: Size

Indicates how many elements are currently in the stack. Think of counting how many plates are stacked.

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Stack: Array Implementation

Implementing a stack using an array, where the top of the stack is represented by an index in the array. Think of the array as a shelf, and the top of the stack points to the last occupied position on the shelf.

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Stack: Array Implementation: Push

In array implementation, pushing adds an element to the top of the stack, incrementing the top index.

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Stack: Array Implementation: Pop

In array implementation, popping removes an element from the top of the stack and decrements the top index.

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Infix to Postfix

Converting an infix expression (where operators are between operands like 10+2*8) into a postfix expression (where operators come after operands like 10 2 8 * +).

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Postfix Evaluation Steps

  1. Create a stack for operands.
  2. Scan the postfix expression, pushing numbers onto the stack and evaluating operators by popping operands, calculating, and pushing the result back.
  3. The final value left in the stack is the result.
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Postfix Expression

An expression where operators follow their operands.

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Operand

A value or variable that is used in an operation.

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Operator

A symbol that indicates an operation to be performed.

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Stack

A data structure that follows the Last-In, First-Out (LIFO) principle, like a stack of plates where you remove the top plate first.

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Push (Stack)

Adding an element to the top of a stack.

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Pop (Stack)

Removing the top element from a stack.

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Postfix Expression Evaluation

Process of calculating the result of a postfix expression by using a stack to store operands and evaluate operators.

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Infix to Postfix Conversion

Converting an infix expression (operators between operands) to a postfix expression (operators after operands) using a stack.

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Precedence

The priority order of operators in an expression. Operators with higher precedence are performed before those with lower precedence (e.g., multiplication (*) has higher precedence than addition (+) ).

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Left Parenthesis '(', Right Parenthesis ')'

Parentheses in infix expressions indicate the order of operations. When encountered while converting to postfix, they act as markers for stack manipulation.

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Push

To add an element to the top of a stack.

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Postfix Notation (Reverse Polish Notation)

A mathematical notation where operators follow their operands. This notation is useful for computers because it simplifies the evaluation process.

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Infix Notation

The standard mathematical notation where operators appear between their operands. It is the way we typically write expressions.

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Stack Implementation using Linked List?

A stack data structure can be implemented using a linked list, where the top of the stack is represented by the head of the list. Pushing and popping operations involve manipulating the head of the list.

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Push in Stack Implementation

The push operation in a stack implemented using a linked list inserts a new node at the beginning of the list. It updates the top pointer to point to the newly added node.

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Pop in Stack Implementation

The pop operation in a stack implemented using a linked list removes the node at the beginning of the list. It returns the data of the removed node and updates the top pointer to point to the next node.

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Stack's Top Node

In a stack implemented using a linked list, the top pointer points to the node at the top of the stack, which is the head of the linked list.

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Reversing Strings using Stack

A stack can be used to reverse a string by pushing each character into the stack and then popping them out one by one. Since the last character pushed is the first popped, the order is reversed.

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Motivation: Stack Applications

Stacks have various applications, including line editing, string reversal, bracket matching, postfix calculations, function call stacks, and keeping track of browser history.

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Stack: Last-In, First-Out (LIFO)

A stack follows the Last-In, First-Out (LIFO) principle, meaning the last element added (pushed) is the first one to be removed (popped).

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Stack: Insert and Remove from Top

In a stack, elements are inserted and removed only from the top, making it a LIFO (Last-In, First-Out) data structure.

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Advantages of Stack Implementation with Linked Lists

Using a linked list for stack implementation provides dynamic memory allocation, avoids overflow issues, and simplifies operations like pushing and popping elements.

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Stack Implementation

The way a stack is built using underlying data structures like arrays or linked lists.

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Array Implementation

Using an array to store the elements of a stack.

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Linked List Implementation

Using a linked list to store the elements of a stack.

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Stack Overflow

A condition that occurs when a stack tries to add an element to a full array implementation. There's no more space.

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Push Operation

Adding a new node to the beginning of the linked list representing the stack. This updates the 'top' pointer to point to the newly added node.

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Pop Operation

Removing the node at the beginning of the linked list representing the stack. The 'top' pointer is updated to point to the next node in the list.

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Stack Applications

Stacks have various applications, including line editing, string reversal, bracket matching, postfix calculation, function call stacks, and keeping track of browser history.

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What does 'top' represent?

In a stack implemented using a linked list, 'top' is a pointer that always points to the node at the top of the stack, which is the head of the linked list.

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Why use a linked list for stack implementation?

Linked lists provide dynamic memory allocation, avoiding the risk of overflow during push operations, and simplifying operations like pushing and popping elements.

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What are the advantages of using Linked List for stack implementation?

Linked lists provide a dynamic memory allocation, avoiding the risk of overflow during push operations, and simplifying operations like pushing and popping elements.

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Parentheses in Conversion

Parentheses group operations, and their presence in infix-to-postfix conversion affects how operators are placed in the postfix expression.

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Conversion Algorithm

A set of rules for converting infix expressions to postfix expressions, typically involving a stack to manage operators.

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Result Postfix Expression

The final expression obtained after converting an infix expression to postfix notation.

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Stack: Push and Pop

Adding an element to the top of a stack is called 'push', removing an element from the top is called 'pop'.

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Evaluate Postfix Expression: Steps

  1. Create a stack for operands. 2. Scan the expression: push numbers, pop operands for operators, calculate, push the result. 3. Final value in the stack is the answer.
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Stack: Linked List Implementation

A stack can be implemented using a linked list. Each node in the linked list represents an element in the stack. The 'top' pointer points to the head of the linked list.

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Stack: Linked List Implementation (Push)

To push an element to a stack implemented with a linked list, a new node is created and inserted at the beginning of the list. The 'top' pointer is updated to point to the newly added node.

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Stack: Linked List Implementation (Pop)

Popping from a stack implemented with a linked list involves removing the node at the beginning of the list. The 'top' pointer is updated to point to the next node in the list.

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Linked List Stack

A stack data structure implemented using a linked list. The 'top' of the stack is the head of the linked list.

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Push Operation (Linked List Stack)

Adding a new element to the top of the stack by inserting a new node at the beginning of the linked list, updating the 'top' pointer.

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Pop Operation (Linked List Stack)

Removing the element from the top of the stack by deleting the first node in the linked list, updating the 'top' pointer to the next node.

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Reversing a String using a Stack

Push characters of a string onto a stack, then pop them off one by one. Because of LIFO, the popped characters will be in reverse order.

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Postfix Evaluation

Evaluating a postfix expression using a stack. Numbers are pushed, operators pop operands, calculate, push the result.

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Operator Precedence

The order in which operators are evaluated in an expression. Operators with higher precedence are performed first (e.g., multiplication * has higher precedence than addition +).

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Stack (in Postfix Evaluation)

A data structure used to temporarily store operands during postfix expression evaluation. Operands are pushed onto the stack and popped when needed to perform operations.

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Stack in Conversion

A stack data structure is used to temporarily store operators during the conversion process. It helps maintain the order of operations and ensures correct postfix expression creation.

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Operator Handling

Operators are handled based on their precedence within the expression. Lower precedence operators are pushed onto the stack, while higher precedence operators are popped and placed in the postfix expression.

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Study Notes

Pointers to Structures

  • Structures group related data
  • Pointers hold memory addresses
  • Pointers allow accessing struct members

Linked Lists

  • Linear data structure
  • Nodes contain data and a pointer to the next node
  • Nodes link together sequentially
  • Each node stores data
  • Each node stores a reference to the next node
  • Head pointer refers to the first node
  • Last node points to NULL

Creating a Linked List

  • No need to specify initial size
  • New nodes added when needed

Traversal

  • Pointer to the initial node, a current node pointer
  • Loop structure to find the last node

Size

  • Counter initialized to zero (count = 0)
  • Traversal through each node
  • Increments counter (count++)
  • Function returns final counter value

Insertion

  • Inserting new nodes in the list
  • Three Insertion methods
    • Inserting at first
    • Inserting at last
    • Inserting at middle (within the list)

Insertion at First (Prepend)

  • Point a new node towards the first node (existing head).
  • Update the head pointer to point to the newly created node

Insertion at Last (Append)

  • Find the last node in the linked list
  • Point the last node's pointer to the new node

Insertion at Position

  • Traverse until reaching the target position for insertion
  • Identify the node before and after the target position for updating pointers
  • Update pointers accordingly

Deletion

  • Find the nodes before and after the target node
  • Update the pointer of the preceding node to the following node
  • Remove (delete) the unwanted node

Searching

  • Initial pointer to the first node in the list
  • Loop to search within the linked list
  • Function returns position if found, otherwise it returns -1

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Related Documents

Lecture 4 - Stacks PDF
Linked List Lecture Notes PDF

Description

Explore the essential concepts of pointers and linked lists in data structures. This quiz covers topics such as node creation, traversal techniques, and various insertion methods. Test your understanding of how pointers interact with structures and the fundamentals of linked lists.

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