Day 13/75: HashMap patterns in Java

75 Day DSA in Java Challenge

Today I focused on using a stable invariant so hashmap patterns in java feels like a process instead of a trick. The strongest checkpoints were name the exact window, prefix, or pointer region each variable owns, reuse prior work instead of recomputing the same range each iteration, and test boundary sizes first because they expose weak invariants quickly.

The mistake I wanted to avoid was moving boundaries before stating what region they actually represent. 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.