Find duplicates in an given array in O(n) time and O(1) extra space.

Objective: Given an array of integers, find out duplicates in it. Example: int [] a = {4, 6, 2, 1, … Read more

Find the last repeating character in a given string.

Objective: Given a string, write an algorithm to find the last repeating character in it. Example: String input = “horizon … Read more

Find Whether Two Strings are Permutation of each other

Objective: Given Two Strings, check whether one string is a permutation of other

Input: Two Strings

Output: True or false based on whether strings are permutations of others or not.


"sumit" and "tiums" are permutations of each other.

"abcd" and bdea" are not permutations of each other.


Method 1: Time Complexity – O(nlgn)

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