AtCoder Regular Contest 058 （组合数学，D - いろはちゃんとマス目 / Iroha and a Grid）
题目链接：https://atcoder.jp/contests/arc058/tasks/arc058_b题目描述：Problem StatementWe have a large square grid withHHrows andWWcolumns. Iroha is now standingin the top-left cell. She will ...
