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Linked List Fundamentals Linked lists consist of nodes connected via pointers, differing from arrays in their non-contiguous memory allocation. Common variants include singly-linked, doubly-linked, and circular linked lists. A basic singly-linked list node structure in C++: struct ListNode { int value; ListNode* next; ListNode(int x ...

1. Linked-list fundamnetals A linked list is a linear collection of nodes where each node stores: value – the payload next – a pointer to the following node (or nullptr) Variants: Singly linked list – one pointer per node Doubly linked list – prev + next Circular linked list – tail points back to head Memory is non-contiguous; traversal is ...

148. Sort List Problem Statement Given the head of a linked list, sort the list in ascending order and return the sorted list. Approach For this problem, we can implement a merge sort algorithm with O(1) space complexity by using a bottom-up approach. The key steps involve: Determining the length of the linked list Splitting the list into subl ...

Swapping Nodes in Pairs Problem: Given a linked list, swap every two adjacent nodes and return the modified list. You must not modify the values in the nodes, only the nodes themselves. The key approach involves careful pointer manipulation and the use of a temporray node to preserve references. We'll use a dummy node to simplify the edge ca ...

A stack is a linear data structure that restricts insertion and deletion operations to one end—commonly referred to as the top. This constraint enforces a Last-In-First-Out (LIFO) behavior: the most recently added element is the first to be removed. Core Terminology Top: The active end where all push and pop operations occur. Bottom: The fixed ...

Header File Inclusion #pragma once #include <stdio.h> #include <stdlib.h> #include <assert.h> Data Type Defniition Using a type alias improves maintainability and simplifies type changes across the codebase: typedef int ElementDataType; Node Structure Definition typedef struct ListNode { ElementDataType value; stru ...

Given a singly linked list, determine weather it contains a cycle. Return true if a cycle exists; otherwise, return false. The solution must use O(1) auxiliary space. This problem is classically solved using Floyd’s Cycle Detection Algorrithm — also known as the "tortoise and hare" approach. Two pointers traverse the list at different ...

1. C Language Examples of Array Pointers, Pointer Arrays, Function Pointers, and Pointer Functions Pointer Array An array where each element is a pointer is called a pointer array. int *ptr_arr[10]; #include <stdio.h> int main() { int arr1[] = {1, 2, 3, 4, 5}; int arr2[] = {6, 7, 8, 9, 0}; int arr3[] = {1, 2, 3, 4, 5}; i ...

Intersection of Linked Lists Problem Link LeetCode 160 Problem Statement Given the heads of two singly linked lists, headA and headB, return the node at which the two lists intesrect. If there is no intersection, return nullptr. The linked lists must retain their original structure after the function returns. You are not allowed to modify th ...

The algorithm works in three phases: Duplicate each node and insert it immediately after its original Copy the random pointers from original nodes to their duplicates Separate the interleaved lists into original and copy C++ Implementation class LinkedListCloner { public: Node* cloneList(Node* head) { if (!head) return nullptr; ...