Algorithms Shortest Subarray with at least K as sum In this problem, we find the length of the Shortest Subarray with at least K as sum. This can be solved in O(N) time complexity. This brings in the ideas of Monotonic Queue and Sliding Window.

Algorithms Number of substrings with exactly k distinct characters In this problem, we are given a string and our job is to count the total number of substrings of the given string that contains exactly k distinct characters. We have explored 3 approaches to solve this.