Is there a mistake of ch9 / UVa1218.cpp ?

[Sengxian]

In line 44 and 45

        if(d[u][0] > INF) d[u][0] = INF; // avoid overflow!
        if(d[u][1] > INF) d[u][1] = INF;

and line 51

        d[u][2] = min(d[u][2], d[u][1] - d[v][2] + d[v][0]); // neither u or father is server

If d[u][1] and d[v][2] are set to INF. d[u][1] - d[v][2] will be a zero, it’s obviously meaningless.

Although it is accepted, it will make mistakes in some test cases. Like

7
1 5
4 1
3 5
2 3
6 5
7 2
-1

the correct ans is 3, but the code get 1.

If we change it to this

                if(d[v][0] > INF) d[v][0] = INF;
                if(d[v][1] > INF) d[v][1] = INF * 2; // avoid INF - INF = 0

It will be all right.