Written by Timevolt
The Quest Begins (The "Why") Ever stared at a coding interview question that asks for the sum of numbers between indices l and r… a hundred times? I have. The first time I saw it, I thought “just loop, it’s fine.” Then the tester dropped a follow‑up: “now do it with updates in between.” My naive O(n) per query solution started to feel like trying to defeat a final boss with a wooden sword. I spent a frustrating afternoon debugging off‑by‑one errors, and when the test suite finally turned gr...