Codeforces Round #238 (Div. 2) D. Toy Sum 暴搜
题目链接：题目D. Toy Sumtime limit per test：1 secondmemory limit per test：256 megabytes问题描述Little Chris is very keen on his toy blocks. His teacher, however,...
Usaco 2.3 Zero Sums(回溯DFS)--暴搜
Zero SumConsider the sequence of digits from 1 through N (where N=9) in increasing order: 1 2 3 ... N.Now insert either a `+' for addition or a `-' fo...