POJ - 2230 - Watchcow【欧拉回路】/补

#include<iostream>
#include<cstdio>
#include<vector>
using namespace std;
const int maxn = 1e4+10;
const int maxm = 4e4+10;
int n, m;
struct Edge{
    int to,flag;
}e;
vector<Edge> edge[maxm*2];
void dfs(int k)
{
    int len = edge[k].size();
    for (int i = 0; i < len; i++)
    {
        if(!edge[k][i].flag)
        {
            edge[k][i].flag = true;
            dfs(edge[k][i].to);
        }
    }
    printf("%d\n", k);
}
int main()
{
    scanf("%d%d", &n, &m);
    for (int i = 0; i < m; i++)
    {
        int a, b;
        scanf("%d%d", &a, &b);
        e.to = b, e.flag = false;
        edge[a].push_back(e);
        e.to = a, e.flag = false;
        edge[b].push_back(e);
    }
    dfs(1);
    return 0;
}