HDOJ-3038(带权并查集)

2019-08-26

How many answers wrong

HDOJ-3038

一个很好的博客:https://www.cnblogs.com/liyinggang/p/5327055.html

#include<iostream>
#include<cstdio>
#include<cstring>
#include<string>
#include<algorithm>
#include<cmath>
using namespace std;
const int maxn=200004;
int n,m;
int set[maxn];
int sum[200004];
int ans;
int find(int x){
    if(x==set[x])
        return set[x];
    else{
        int parent=set[x];
        set[x]=find(set[x]);
        sum[x]+=sum[parent];
        return set[x];
    }
}
void merge(int a,int b,int w){
    a--;
    int ta=find(a);
    int tb=find(b);
    if(ta==tb){
        if(sum[a]-sum[b]!=w)
         ans++;
    }else{
        set[ta]=tb;
        sum[ta]=sum[b]-sum[a]+w;
    }
}
int main(){
    while(cin>>n>>m){
        for(int i=0;i<=n;i++){
            sum[i]=0;
            set[i]=i;
        }
        ans=0;
        int x,y,z;
        for(int i=1;i<=m;i++){
            cin>>x>>y>>z;
            merge(x,y,z);
        }
        cout<<ans<<endl;
    }
    return 0;
}