Codeforces Round #536 (Div. 2)--1106D - Lunar New Year and a Wander

#include<bits/stdc++.h>
using namespace std;

int main(){
    int n,m;
    cin>>n>>m;
    vector<vector<int> > g(n+1);
    for(int i=0;i<m;i++){
        int a,b;
        cin>>a>>b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    vector<int> visit(n+1);
    vector<int> path;
    priority_queue<int,vector<int>,greater<int> > q;
    q.push(1);
    visit[1]=1;
    while(!q.empty()){
        int c=q.top();
        q.pop();
        path.push_back(c);
        for(int j=0;j<g[c].size();j++){
            int d=g[c][j];
            if(visit[d]!=1){
                q.push(d);
                visit[d]=1;
            }
        }
    }
    for(int i=0;i<path.size();i++){
        cout<<path[i]<<‘ ‘;
    }
    cout<<endl;
    return 0;
}