题意:给了n个物品,每个物品有两个值,H和C 问你怎么取, 使最后
$$(\sum_{i=1}^{m} H_{x_i})^2-(\sum_{i=1}^{m} H_{x_i})\times(\sum_{i=1}^{m} C_{x_i})-(\sum_{i=1}^{m} C_{x_i})^2$$$$(\sum_{i=
题意:给了n个物品,每个物品有两个值,H和C 问你怎么取, 使最后
$$(\sum_{i=1}^{m} H_{x_i})^2-(\sum_{i=1}^{m} H_{x_i})\times(\sum_{i=1}^{m} C_{x_i})-(\sum_{i=1}^{m} C_{x_i})^2$$$$(\sum_{i=