HDU 1272（并查集）

来源：互联网发布：十分钟看懂时序数据库编辑：程序博客网时间：2024/05/06 03:53

#include<stdio.h>#include<stdlib.h>#include<algorithm>#include<math.h>#include<string.h>#include<queue>#include<vector>#include<map>using namespace std;#define rep(i,n) for(int (i)=1;(i)<=(int)(n);++(i))const int MAXN=100005;int from[MAXN],to[MAXN];int father[MAXN];int Find(int x){    if(x==father[x]) return x;    return father[x]=Find(father[x]);}int main(){    //freopen("test.txt","r",stdin);    int a,b;    int n=0,m=0,cnt=0,ans=0;    while(scanf("%d%d",&a,&b)&&(a!=-1&&b!=-1))    {        father[a]=a,father[b]=b;        if(a&&b)        {            from[++m]=a;to[m]=b;            continue;        }        rep(i,MAXN) if(father[i]==i)n++;        rep(i,m)        {            int ff=Find(from[i]),ft=Find(to[i]);            if(ff==ft) {ans=1;break;}<span style="white-space:pre"></span>    else        {            father[ff]=ft;            cnt++;        }        }        if(!ans&&(cnt==n-1||n==0)) printf("Yes\n");        else printf("No\n");        memset(father,0,sizeof(father));        n=0,m=0,cnt=0,ans=0;    }    return 0;}

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