Hello and welcome to another coding interview test challenge.

Today we’ll be dealing with strings & substrings. Know the answer? Write it in a gist on github and leave a link to it in the comments below!

Given an integer k and a string s, find the length of the longest substring that contains at most k distinct characters.

For example, given s = “abcba” and k = 2, the longest substring with k distinct characters is “bcb”.