Fleury算法 求欧拉回路

Fleury算法

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <algorithm>
 #include <climits>
 #include <vector>
 #include <queue>
 #include <cstdlib>
 #include <string>
 #include <set>
 #include <stack>
 #define LL long long
 #define pii pair<int,int>
 #define INF 0x3f3f3f3f
 using namespace std;
 const int maxn = ;
 bool e[maxn][maxn];
 int n,m;
 stack<int>stk;
 void dfs(int u){
     stk.push(u);
     for(int i = ; i <= n; i++){
         if(e[u][i]){
             e[u][i] = false;
             e[i][u] = false;
             dfs(i);
             break;
         }
     }
 }
 void Fleury(int x){
     while(!stk.empty()) stk.pop();
     stk.push(x);
     int i;
     while(!stk.empty()){
         int u = stk.top();
         stk.pop();
         for(i = ; i <= n; i++)
             if(e[u][i]) break;
        if(i <= n) dfs(u); else printf("%d ",u);
     }
     puts("");
 }
 int main() {
     int u,v,cnt,degree,st;
     while(~scanf("%d %d",&n,&m)){
         memset(e,false,sizeof(e));
         for(int i = ; i < m; i++){
             scanf("%d %d",&u,&v);
             e[u][v] = e[v][u] = true;
         }
         cnt = ;
         st = ;
         for(int i = ; i <= n; i++){
             for(int j = ,degree = ; j <= n; j++)
                 if(e[i][j]) degree++;
             if(degree&){
                 st = i;
                 cnt++;
             }
         }
         if(cnt ==  || !cnt) Fleury(st);
         else puts("No Euler path");
     }
     return ;
 }