考虑枚举构成最大前缀和的数，这样就需要计算 $f(S)$ 为 $S$ 的排列，严格最大前缀和为 $\sum_{i\in S} a_i$ 的方案数，和 $g(S)$ 为 $S$ 的排列，前缀和均 $\le 0$ 的方案数。
$g$ 是容易做的，$f$ 的话要考虑往前面加数。
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Discussion #829 for Problem #10508. 最大前缀和
Type: Editorial
Status: Open
Posted by: Qingyu
Posted at: 2026-01-28 02:09:35
Last updated: 2026-01-28 02:09:41
简要题解
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