Two-Pointers

Add two numbers represented as linked lists where digits are stored in reverse order

Find the celebrity in a party of n people using the minimum number of questions.

Determine if a string reads the same forwards and backwards, ignoring case and non-alphanumeric characters.

Detect if a linked list has a cycle and find the starting point of the cycle

Detect if a linked list has a cycle using Floyd's cycle detection algorithm

Find the duplicate number in an array containing n+1 integers where each integer is between 1 and n (inclusive)

Find the middle node of a linked list using the two-pointer technique

Find the first occurrence of a substring in a string, similar to strstr() function.

Find the intersection of two arrays and return the result as an array.

Find the intersection node of two linked lists

Find the longest palindromic substring in a given string

Find the length of the longest substring without repeating characters

Merge two sorted arrays into a single sorted array in-place

Merge two sorted linked lists into one sorted linked list

Find the minimum window substring that contains all characters of another string

Move all zeros in an array to the end while maintaining the relative order of non-zero elements

Check if a linked list is a palindrome using O(1) extra space

Partition a linked list around a value x such that all nodes less than x come before nodes greater than or equal to x

Return an array where each element is the product of all elements except the element at that index.

Remove all duplicate values from a sorted linked list

Remove the nth node from the end of a linked list in one pass

Reorder a linked list by interleaving nodes from the beginning and end

Reverse a singly linked list in-place

Reverse the order of elements in an array in-place and return the modified array

Reverse a string in-place using O(1) extra memory.

Rotate a linked list to the right by k places

Find the smallest substring that contains all characters of a given pattern

Compress a string by replacing consecutive characters with character and count.

Find a subarray with a given sum in an array of positive integers.

Find all unique triplets in the array which gives the sum of zero

Calculate how much rainwater can be trapped between bars of different heights

Find two numbers in an array that add up to a target value.