Challenge: sum of squares. Let's break 299

[Thomas Okken]

(01-19-2018 06:31 AM)Paul Dale Wrote:  Instead of a brute force backtracking algorithm, build a graph with the numbers as nodes and edges where they sum to a square. Then find a Hamilton walk with a backtracking search.

Why would that perform any better than my algorithm? For each number, I'm already finding potential successors in O(1) time, and I'm eliminating already-visited numbers with an array lookup. Using a graph *might* be more efficient by some constant, but it won't do anything for the overall time complexity.