2013-09-27から1日間の記事一覧
public class Excavations2 { long?[,] choose = new long?[55, 55]; long Choose(int s, int t) { if (!choose[s, t].HasValue) { if (t == 0 || t == s) choose[s, t] = 1; else choose[s, t] = Choose(s - 1, t - 1) + Choose(s - 1, t); } return choose…