【CodeVS4246】奶牛的身高

#include<iostream>
#include<cstdio>
#define N 1010
using namespace std;
struct node
{
    int fa,val;
}cow[N];
int T,n,m;
int root(int x)
{
    if (cow[x].fa == x) return x;
    int y=cow[x].fa; // fa的值会改变,先记录一下 
    cow[x].fa = root(cow[x].fa);
    cow[x].val = cow[x].val+cow[y].val;
    return cow[x].fa;
}
int main()
{
    int s,t,v,ans;
    scanf("%d",&T);
    for (int I=1;I<=T;I++)
    {
        ans=1;
        scanf("%d%d",&n,&m);
        for (int i=1;i<=n;i++)
        {
            cow[i].fa = i;
            cow[i].val = 0;
        }
        for (int i=1;i<=m;i++)
        {
            scanf("%d%d%d",&s,&t,&v);
            if (!ans) continue;
            if (s == t && v!=0)
            {
                ans = 0;
                continue;
            }
            int fx=root(s),fy=root(t);
            if (fx != fy)
            {
                cow[fx].fa=fy;
                cow[fx].val=cow[t].val-cow[s].val+v; //算一下 
            }
            else
            {
                if (cow[t].val+v != cow[s].val)
                    ans=0;
            }
        }    
        if (ans) printf("Bessie‘s eyes are good\n");
        else printf("Bessie is blind.\n");
    }
}