今日发癫

· · 闲话

[x^{i}](qG(x) + 1 - q)^{n} = [x^{i}]\binom{n}{i}q^{i}(1 - q)^{i}G(x)^{i}

你说得不对，正确形式长这样：

\sum\limits_{i = 1}^{n}\sum\limits_{j = 1}^{n}\left( \min\limits_{x \in \{ A, B, C, D \}}(x_{i} + x_{j}) + \max\limits_{x \in \{ A, B, C, D \}}(x_{i} + x_{j}) \right)

你先别急，