BFS STL....3

//bfs code 3

#include<bits/stdc++.h>
using namespace std;
const int N = (int)1e5 + 5;
vector<int>g[N];
bool visit[N];
int main()
{
    int m, n, i;
    cin >> m >> n;
    for (i = 0; i < n; i++)
    {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);

    }
    queue<int>q;
    q.push(1);
    while (q.size())
    {
        int u = q.front();
        if(!visit[u])
        cout << u << " ";
        q.pop();
        visit[u] = true;
        for (i = 0; i < g[u].size(); i++)
        {
            int v = g[u][i];
            if (!visit[v])
            {
                q.push(v);
            }
        }

    }
    return 0;
}