想到个换根 DP 解法，去敲了
by TDoG_W @ 2024-01-27 20:55:40
用不着换根 DP，实际上确实树上差分 + 树形 DP 可解
by TDoG_W @ 2024-01-27 21:20:10
@[TDoG_W](/user/416578) 我觉得随便搞个前缀和算算就可以了
by Miss_SGT @ 2024-01-27 21:23:20
@[Miss_SGT](/user/705012) 哦，启发式合并
by Miss_SGT @ 2024-01-27 21:24:30
@[Miss_SGT](/user/705012) dsu on tree 应该也确实可以
by TDoG_W @ 2024-01-27 21:27:30