hdu_1272 小希的迷宫

#include <iostream>#include <cstdio>#include <cmath>#include <algorithm>#include <cstring>using namespace std;#define N 100005int Father[N];int visit[N];void Make_set(int n){    for(int i=0; i<=n; i++)        Father[i] = i;}int Find_set(int x){    int pre,temp,ans;    pre = x;    while(x != Father[x])    {        x = Father[x];    }    ans = x;    while(pre != Father[pre])    {        temp = Father[pre];        Father[pre] = ans;        pre = temp;    }    return ans;}void Union_set(int a,int b){    int x = Find_set(a);    int y = Find_set(b);    Father[y] = x;}int main(){    int n,m,i,j,k,temp1,temp2,flag,sum;    while(cin>>temp1>>temp2)    {        memset(visit,0,sizeof(visit));        visit[temp1] = visit[temp2] = 1;        Make_set(N);        flag = 0, sum = 0;        if(temp1==-1&&temp2==-1)            break;        if(temp1==0&&temp2==0)        {            cout<<"Yes"<<endl;            continue;        }        if(Find_set(temp1)==Find_set(temp2))            flag = 1;        else            Union_set(temp1,temp2);        while(cin>>n>>m)        {            if(n==0&&m==0)                break;            visit[n] = visit[m] = 1;            if(flag)                continue;            if(Find_set(n)==Find_set(m) || n==m)                flag = 1;            else                Union_set(n,m);            //cout<<Find_set(n)<<" "<<Find_set(m)<<endl;        }        for(i=1;i<=N;i++)            if(visit[i] && i == Find_set(i))               sum++;        if(!flag&&sum==1)            cout<<"Yes"<<endl;        else            cout<<"No"<<endl;    }    return 0;}