hdu 3038 并查集

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
#include<map>
using namespace std;
#define MOD 1000000007
const int INF=0x3f3f3f3f;
const double eps=1e-5;
typedef long long ll;
#define cl(a) memset(a,0,sizeof(a))
#define ts printf("*****\n");
const int MAXN=200010;
int n,m,tt;
int ans=0;
int f[MAXN];
int val[MAXN];
int find(int x)
{
if(f[x]==-1)    return x;
int temp=find(f[x]);
val[x]+=val[f[x]];
return f[x]=temp;
}
void bing(int x,int y,int w)
{
int t1=find(x);
int t2=find(y);
if(t1!=t2)
{
f[t2]=t1;
val[t2]=val[x]-val[y]+w;
}
else
{
if(val[y]-val[x]!=w)
{
ans++;
}
}
}
int main()
{
int i,j,k;
#ifndef ONLINE_JUDGE
freopen("1.in","r",stdin);
#endif
while(scanf("%d%d",&n,&m)!=EOF)
{
memset(f,-1,sizeof(f));
memset(val,0,sizeof(val));
ans=0;
int u,v,w;
for(i=0;i<m;i++)
{
scanf("%d%d%d",&u,&v,&w);
u-=1;
bing(u,v,w);
}
printf("%d\n",ans);
}
}