AtCoder Beginner Contest 221 Posted on 2021-10-07 Edited on 2022-02-24 In AtCoder rounds AtCoder Beginner Contest 221 G - Jumping sequence 坐标轴旋转\(45^\circ\),转化为2个01背包。 H - Count Multiset 差分数列计数+前缀和优化 差分前: \[ f_{n,k}\leftarrow f_{n-ci,k-i} \] 差分后: \[ g_{k,s}\leftarrow_{i\lt m} g_{k-i,s-kj} \]