Longest Subarray with Sum K: Optimal DSA Guide

The provided transcript details various algorithmic strategies for solving the longest subarray with sum K problem. The instructor breaks down the fundamental definition of a subarray as a contiguous portion of an original array, distinguishing it from a subsequence. The tutorial progresses from a brute-force approach with cubic time complexity to an optimised quadratic version that eliminates redundant calculations. Furthermore, it introduces a better solution using hashing and prefix sums, which is notably effective for arrays containing negative numbers. Finally, an optimal two-pointer greedy technique is demonstrated for arrays with only positive integers and zeros, achieving linear time complexity.