uva-10596-欧拉回路

#include <iostream>
#include<memory.h>
#include<stdio.h>
using namespace std;

const int N = 205;

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

int find(int key, int a[N])
{
    return key == a[key] ? key : a[key] = find(a[key], a);
}
void join(int k1, int k2, int a[N])
{
    int p1 = find(k1, a);
    int p2 = find(k2, a);
    if (p1 != p2)
    {
        if (p1 < p2)
            a[p2] = p1;
        else
            a[p1] = a[p2];
    }
}

int main()
{
    freopen("d:\\1.txt", "r", stdin);
    int n, m;
    while (cin >> n >> m)
    {
        if(m==0)
        {
            cout<<"Not Possible"<<endl;
            continue;
        }
        int a[N];
        int du[N];
        initSet(a);
        memset(du, 0, sizeof(du));
        int s, e;
        for (int i = 0; i < m; i++)
        {
            cin >> s >> e;
            du[e]++;
            du[s]++;
            join(s,e,a);
        }
        int ok = 1;
        for (int i = 0; i < n; i++)
            if (du[i] %2 !=0)
            {
                ok = 0;
                break;
            }
        int  p = find(s,a);
        //联通
        for (int i = 0; i < n; i++)
        {
            if (find(i, a) != p && du[i]!=0)
            {
                ok = 0;
                break;
            }
        }
        if (ok)
            cout << "Possible" << endl;
        else
            cout << "Not Possible" << endl;
    }
    return 0;
}