欧拉图bz

给一个无向图，输出欧拉图顺序

//答案存在了ans数组，abs[1-t]
int sta[1000010],ans[1000010],vis[1000010];
int n,m,top,t;
void euler()
{
    sta[++top] = 1;
    while(top > 0)
    {
        int x = sta[top], i = head[x];
        while(i && vis[i])    i = Next[i];    //找到一条尚未访问过的边
        if(i)
        {
            sta[++top] = ver[i];
            vis[i] = vis[i ^ 1] = true;
            head[x] = nextt[i];
        }else{          //x连接的所有边都已经访问过了，回溯，级在答案栈中
            top--;
            ans[++t] = x;
        }
    }
}
// main
scanf("%d%d", &n, &m);
tot = 1;
int x, y;
for(int i = 0; i < m; ++i)
{
    scanf("%d%d", &x, &y);
    add(x, y);
    add(y, x);
}
euler();
for(int i = t; i; --i)
{
    printf("%d\n", ans[i]);
}