OJ Board

Ok, finally, I understand why a judge can judge a segment of participants... A maximum flow with minimum cost algorithm can be used.

This is quite a strange problem. I have been thinking about the algorithm for a long time. I tried to solve this problem using maximum flow with minimum cost, but at last, I didn't come up with the right solution. Also, I don't know whether a greedy algorithm exists.
So, can someone give some ...

I have a problem on UVA 3562... I used Igor's code to find the min cost, and then negated all the edges. I tried to use BellmanFord algorithm to find every circle with negative cost, and delete them. So, At last, my algorithm could get the max cost. But, I got WA and my program ran really slowly ...

I have a problem on UVA 3562... I used Igor's code to find the min cost, and then negated all the edges. I tried to use BellmanFord algorithm to find every circle with negative cost, and delete them. So, At last, my algorithm could get the max cost. But, I got WA and my program ran really slowly - 2 ...

I really want to know what your algorithm is. I know I can use a segment tree or something like this, but I really don't know HOW to use it.
I'm interested in your O(log N) solution, so can you explain it more carefully, or do you have any lecture about it?