hdu3047之并查集

#include<iostream>#include<cstdio>#include<cstdlib>#include<cstring>#include<string>#include<queue>#include<algorithm>#include<map>#include<iomanip>#define INF 99999999using namespace std;const int MAX=50000+10;const int mod=300;int father[MAX],dist[MAX],sum;void makeset(int num){for(int i=0;i<=num;++i){father[i]=i,dist[i]=0;}}int findset(int v){if(v == father[v])return father[v];int temp=findset(father[v]);dist[v]=(dist[v]+dist[father[v]])%mod;//在递归回溯的时候求子节点到父节点的距离 father[v]=temp;return father[v]; }void Union(int x,int y,int l){int a=findset(x);int b=findset(y);if(a == b){if((dist[y]-dist[x]+mod)%mod != l)++sum;}else{dist[b]=dist[x]+l-dist[y];//y的父节点b到a的距离if(dist[b]<0)dist[b]+=300;//b在a的左边 if(dist[b]>=mod)dist[b]%=mod;//b的座位数顺时针一个圈绕回去了 father[b]=a; }}int main(){int n,m,a,b,c;while(scanf("%d%d",&n,&m)!=EOF){makeset(n);sum=0;for(int i=0;i<m;++i){scanf("%d%d%d",&a,&b,&c);Union(a,b,c);}cout<<sum<<endl;}return 0;}