# Reverse the LinkedList

# Find length of longest substring of given string.

In this algorithm we just need length of longest sub string of given string. We are going to solve this by O(n) Example : Input : zabac Output : 3 Just take a queue and add character in it one by one. Just before adding any new char, check if it is already there then… Read more

# Add two non-empty linked lists representing two non-negative integers

You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list. You may assume the two numbers do not contain any leading zero, except the number 0 itself.

# Find an element in array after rotating an array by k steps to the right

Rotate an array of n elements to the right by k steps and then find an element at particular position in array. For example, with n = 5 and k = 3, the array [1,2,3,4,5] is rotated to [4,5,1,2,3]. Now after rotation we need element at position 3 which is 2 Consider this array as… Read more

# Two Sum

# Find cycle/loop in the graph – method 1

Find below algorithm to find loop/cycle in graph, Here in each stage I am checking for child node visited state. If any of the parent node has more than one child with visited state then it means graph has a loop. We can also use Disjoint Set (Or Union-Find) which I’ll show you in next… Read more