Teaching Kids Programming – Minimum Number of Perfect Squares via Theorem-guided iterative deepening DFS

This article explores an iterative-deepening recursive solution to LeetCode 279, Perfect Squares. By combining depth-limited search with Lagrange’s Four Square Theorem, we only need to test whether a number can be represented using one, two, or three perfect squares—otherwise, the answer must be four. The approach is also compared with dynamic programming, BFS, and a pure number-theory solution.…