YoungForest's blog

A practical guide to queues and stacks, covering implementations, circular queues, BFS, DFS, and building one structure from the other.

Four contest solutions cover cousin nodes, multi-source BFS for rotting oranges, greedy fixed-window flips, and square-sum permutations.

A structured guide to recursion, recurrence relations, memoization, complexity analysis, call stacks, and tail-recursion optimization.

Post-holiday contest notes on digitwise addition, union-find, reverse calculator reasoning and two-window distinct-subarray counting.

New Year's Eve catch-up and interview reflection through even-sum queries, leaf-to-root strings, interval intersections and vertical tree traversal.

Travel-day contest and phone-interview notes on alternating strings, time maps, ticket costs, bitwise triples and communicating under pressure.

A friendly contest milestone through sorted squares, turbulent runs, coin distribution in trees and a backtracking path over every grid cell.

A contest setback revisited through closest points, maximum-perimeter triangles, matched prefix remainders and ordered odd-even jumps.

Progress after switching to C++ through power sums, pancake sorting, tree flips, rational equality and renewed language fundamentals.

An experiment in blogging during the contest, covering univalued trees, equal adjacent differences, spell filters and observation lamps.