hdu1878

/*
 * File:    * 判断是否存在欧拉回路，存在欧拉回路的条件：所有顶点的度为偶数，并且图是联通的
 * 判断顶点的度是否为偶数只要进行统计判断就行，判断图的联通可以用并查集，判断所
 * 有的顶点是否在一棵树上。
 * Author: chenjiang
 *
 * Created on 2010年5月7日, 下午1:21
 */

#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <algorithm>
#include <stdio.h>
using namespace std;
#define _max 1005
int p[_max], rank[_max];
int degree[_max];

void init_set(int n) {//并查集初始化
    for (int i = 1; i <= n; i++) {
        p[i] = i;
        rank[i] = 0;
    }
}

int getfather(int x) {//找x说属树的根节点
    if (p[x] != x)p[x] = getfather(p[x]);
    return p[x];
}

void Union(int a, int b) {//把a和b合并在一棵树上
    a = getfather(a);
    b = getfather(b);
    if (p[a] == p[b])return;
    if (rank[a] > rank[b]) {
        p[b] = a;
        rank[a] += rank[b];
    } else {
        p[a] = b;
        rank[b] += rank[a];
    }
}

/*
 *
 */
int main(int argc, char** argv) {

    int i, j, a, b, n, m;
    while (cin >> n) {
        if (n == 0)break;
        cin >> m;
        memset(degree, 0, sizeof (degree));//度初始化
        init_set(n);
        for (i = 1; i <= m; i++) {
            cin >> a >> b;
            Union(a, b);
            degree[a]++;
            degree[b]++;
        }
        bool flag = 0;
        if (degree[1] % 2 != 0)flag = 1;
        int root = getfather(1);
        for (i = 2; i <= n; i++) {
            int k = getfather(i);
            if (k != root)
            {
                flag = 1;break;
            }
            if (degree[i] % 2 != 0)
            {
                flag = 1;break;
            }
        }
        if (flag)cout << 0 << endl;
        else cout << 1 << endl;
    }
    return (EXIT_SUCCESS);
}

 

 

 

 

/*
 * File:   hdu1878.cpp
 * 用深搜判断连通性
 * Author: chenjiang
 *
 * Created on 2010年5月7日, 下午1:52
 */

#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <stdio.h>
#include <algorithm>
using namespace std;
#define _max 1005
int degree[_max];
int mapmap[_max][_max];
bool visited[_max];
int n, m;
int num;

void dfs(int k) {
    int i;
    num++;
    visited[k] = 1;
    for (i = 1; i <= n; i++) {
        if (mapmap[k][i] && !visited[i]) {
            dfs(i);
        }
    }
}

/*
 *
 */
int main(int argc, char** argv) {

    int i, j, k, a, b;
    while (cin >> n) {
        if (n == 0)break;
        cin >> m;
        memset(degree, 0, sizeof (degree));
        memset(mapmap, 0, sizeof (mapmap));
        for (i = 1; i <= m; i++) {
            cin >> a >> b;
            mapmap[a][b] = mapmap[b][a] = 1;
            degree[a]++;
            degree[b]++;
        }
        bool flag = 1;
        for (i = 1; i <= n; i++) {
            if (degree[i] % 2 != 0) {
                flag = 0;
                break;
            }
        }
        if (flag) {
            memset(visited, 0, sizeof (visited));
            num = 0;
            dfs(1);
            if (num == n)cout << 1 << endl;
            else cout << 0 << endl;
        } else {
            cout << 0 << endl;
        }
    }
    return (EXIT_SUCCESS);
}