Longest Substring with at Least K repeating characters

In this article, we have presented two algorithms to find the Longest Substring with at Least K repeating characters.

Table of contents:

Problem StatementApproach 1Approach 2Problem Statement

Before we dive into the problem, lets understand the problem statement more clearly:

Given a string s and an integer k, find the length of the longest substring such that the frequency of each character in this substring is greater than or equal to k

That sounds easy enough right? Lets look at a few ex...