【歐拉迴路】hdu 1878

判是否是歐拉迴路，方法：先判連通性，再判度數是否全是偶數

#include <map>#include <set>#include <list>#include <queue>#include <deque>#include <stack>#include <string>#include <time.h>#include <cstdio>#include <math.h>#include <iomanip>#include <cstdlib>#include <limits.h>#include <string.h>#include <iostream>#include <fstream>#include <algorithm>using namespace std;#define LL long long#define MIN INT_MIN#define MAX INT_MAX#define pii pair<int ,int>#define mp make_pair#define PI acos(-1.0)#define FRE freopen("input.txt","r",stdin)#define FF freopen("output.txt","w",stdout)#define N 1005vector<int> v[N];bool vis[N];int cnt;int du[N];void dfs(int x) {    int i,j;    vis[x] = 1;    for (i = 0 ; i < v[x].size(); i++) {        int y = v[x][i];        if (!vis[y]) {            vis[y] = 1;            cnt++;            dfs(y);        }    }}int main(){    int n,m;    while(scanf("%d%d",&n,&m) && n) {        int i,j;        for (i = 0 ; i <= n; i++) {            v[i].clear();            vis[i] = 0;            du[i] = 0;        }        while(m--) {            int x,y;            scanf("%d%d",&x,&y);            v[x].push_back(y);            v[y].push_back(x);            du[x]++;            du[y]++;        }        cnt = 1;        dfs(1);        if (cnt == n) {            bool ok = 1;            for (i = 1; i <= n; i++) {                if (!du[i] || (du[i]&1)) {                    ok = 0;                    break;                }            }            if (ok) {                printf("1\n");            } else printf("0\n");        } else printf("0\n");    }    return 0;}