Day 17/75: Binary search basics

75 Day DSA in Python Challenge

Today I focused on protecting the search interval in binary search basics so every bound update stays justified. The strongest checkpoints were state what the active interval still allows before the first loop iteration, move left and right only when the predicate proves one side is impossible, and test the smallest failing boundary because off-by-one errors hide there first.

The mistake I wanted to avoid was moving left and right without a precise definition of what they still allow. The day felt better once the invariant stayed visible and each update had one job.

The goal for tomorrow is simple: keep the rule clear enough that the next variation still feels related to the same idea. I also want to keep tracing tiny examples because they expose weak assumptions faster than large random tests. I also want to keep tracing tiny examples because they expose weak assumptions faster than large random tests.