摘要：题目描述 LiLand is a country, consisting of \(n\) cities. The cities are numbered from \(1\) to \(n\) . The country is well known because it has a very st 阅读全文

摘要：差分约束可以求出这样的不等式组的 \(\{x_i\}\) 的一组整数解 \[ x_{a_1}-x_{b_1} \le c_1\\ x_{a_2}-x_{b_2} \le c_2\\ \vdots\\ x_{a_n}-x_{b_n} \le c_n\\ \] 对于一个不等式可以移个项 \(x_{a_i 阅读全文