c++骑马修栅栏(栈)

#include <iostream>
#include <algorithm>
#include <stack>
#include <vector>
#include <set>
#include <unordered_map>
using namespace std;
int n,min_n=600;
unordered_map<int,multiset<int>> fence; //存栅栏边(multiset存多个值且自动升序)
unordered_map<int,int> degree; //节点度数
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cin>>n;
    for(int i=0;i<n;i++){
        int x,y;
        cin>>x>>y;
        fence[x].insert(y);
        fence[y].insert(x);
        degree[x]++;
        degree[y]++;
        min_n=min(min_n,x); //起点
        min_n=min(min_n,y);
    }
    vector<int> odds; // 存奇度数
    for (auto it = degree.begin(); it != degree.end(); ++it) {
        if (it->second % 2 != 0) {
            odds.push_back(it->first);
        }
    }
    //数据保证图是连通的
    int start=min_n;
    if(!odds.empty()){
        start=min(odds[0],odds[1]); //可能图为欧拉回路也有可能就是欧拉路径
    }
    stack<int> skt;
    vector<int> path; //欧拉路径
    skt.push(start);
    while(!skt.empty()){
        int u=skt.top(); 
        if(!fence[u].empty()){
            int v=*fence[u].begin(); //每次采取最小节点路径
            fence[u].erase(fence[u].begin());
            fence[v].erase(fence[v].find(u));
            skt.push(v); //压栈
        }
        else{
            path.push_back(u);
            skt.pop();
        }
    }
    reverse(path.begin(),path.end()); //逆序
    for(auto i:path){
        cout<<i<<endl;
    }
    return 0;
}