[bzoj1202][HNOI2005]狡猾的商人[并查集]

#include <cstdio>
#include <iostream>
#include<cstring>
using namespace std;
int w;
int n,m;
int s,t,v;
int fa[102];
int v1[102];
bool flag;
int parent;
inline int get(int x)
{
if (fa[x]==x) return x;
parent=get(fa[x]);
v1[x]+=v1[fa[x]];
fa[x]=parent;
return fa[x];
}
inline void work(int x,int y,int z)
{
int xf=get(x);int yf=get(y);
if (xf!=yf)
{
fa[xf]=yf;
v1[xf]=v1[y]-v1[x]-z;
}
else if (v1[y]-v1[x]!=z) flag=true;
}
int main()
{
scanf("%d",&w);
for (register int i=1;i<=w;i++)
{
memset(v1,0,sizeof(v1));
flag=0;
scanf("%d%d",&n,&m);
for (register int j=0;j<=n;j++) fa[j]=j;
for (register int j=1;j<=m;j++)
{
scanf("%d%d%d",&s,&t,&v);
work(s-1,t,v);
}
if (flag) printf("false\n");
else printf("true\n");
}
return 0;
}