hdu1878 判斷一個無向圖是否存在歐拉回路模板

#include <iostream>
#include<algorithm>
#include<bits/stdc++.h>
using namespace std;


const int N=1001;
int n,m,fa[N];
int degree[N],sum;

void init()
{
    for(int i=0;i<N;i++)
        fa[i]=i;
}

int find(int x)
{
    if(x==fa[x])return x;
    else return fa[x]=find(fa[x]);
}


void Union(int x,int y)
{
    x=find(x);y=find(y);
    if(x==y)return ;
    fa[x]=y;
    sum--;
}
int main()
{
    while(cin>>n&&n){
        cin>>m;
        memset(degree,0,sizeof(degree));
        init();
        sum=n;
        int a,b;
        for(int i=0;i<m;i++){
            cin>>a>>b;
            degree[a]++;
            degree[b]++;
            Union(a,b);
        }
        if(sum==1){
            bool flag=true;
            for(int i=1;i<=n;i++)
            if(degree[i]&1){
                flag=false;
                break;
            }
            if(flag)cout<<"1"<<endl;
            else cout<<"0"<<endl;
        }
        else cout<<"0"<<endl;
    }
    return 0;
}