I also have WA5((

OH!!!!FT..
Realy, It's the problem ~
I didn't know that long long is not supported ,either ~
maybe the judge should update its compiler?

I know abbreviations AC, WA, TLE, DFS, BFS, DP... But what does FT stand for???

Had a very silly WA6, and none of tests from this or neighbouring topics helped, so here's the one that i finally thought of and which helped:
5
1 1
01000
10001
00010
00101
01010
(1-2, 2-5, 5-4, 4-3, result is all zeros.)
I've been sleepy and lazy and did a bad job with a tree building algo, which i made like this:
---
(mark vertices 1..N as unconnected)
for i:=1 to N do
    for j:=1 to N do
        if (i, j) is an existing edge and either i or j is yet unconnected to anything,
            then add (i, j) to a tree and mark both i and j as connected.
---
So then it adds 1-2, then 2-5, then 3-4, and then it appears that both 4 and 5 are already connected to something, and 4-5 isn't included to a tree, which is a mistake.

The project is not very difficult. The test is so easy. ^^

Thanks for the help...i spent a day debug my code :)