The Quest Begins (The "Why") I still remember my first technical interview like it was yesterday. I was nervous, my palms were sweaty, and the interviewer tossed over a seemingly simple problem: “Given an array of integers, return the length of the longest subarray that sums to zero.” I dove in, started coding a brute‑force double loop, and watch the clock tick. Ten minutes later I had a working solution… but it was O(n²) and looked like a bowl of spaghetti. The interviewer nodded politely...