DQS的树洞

分数规划。二分答案，用输入的权值减去答案。判负环。需要用dfs判负环，spfa会T。dfs判负环： 初始dist都为0。只走能更新dist的点。若走到了vis=1的点，则有负环。代码：#include<cstdio>#include<iostream>#include<algorithm>#include<cstring>#include<cmath>#include<queue>us

Network of Byteland consists of n servers, connected by m optical cables. Each cable connects two servers and can transmit data in both directions. Two servers of the network are especially important —