bfs.cpp

#include <iostream>
#include <cmath>
#include <stack>
#include <cstring>
#include <stdlib.h>
#include <unordered_set>
#include <vector>
#include <map>
#include <set>
#include <unordered_map>
#include <algorithm>
#include <queue>
using namespace std;
#define vi vector<int>
#define vvi vector<vi>
#define pii vector<int, int>
#define vii vector<pii>
#define rep(i, a, b) for (int i = a; i < b; i++)
#define ff first
#define ss second
const int N=1e5+2;
bool vis[N];
vi adj[N];
int main(){
    rep(i,0,N){
        vis[i]=0;
    }
    int n=7,m=7;
    rep(i,0,m){
        int x,y;
        cin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
        

    }
    queue<int> q;
    q.push(1);
    vis[1]=1;
    while(!q.empty()){
        int node=q.front();
        q.pop();
        cout<<node<<endl;
        vi :: iterator it;
        for(it=adj[node].begin();it!=adj[node].end();it++){
            if(!vis[*it]){
                vis[*it]=1;
                q.push(*it);
            }
        }
    }
    return 0;
}
vector<int> bfs(int v , vi adj[]){
    vector<int> vis(v,0);
    vector<int> ans;
    queue<int> q;
    q.push(0);
    vis[0]=1;
    while(!q.empty()){
        int node=q.front();
        q.pop();
        ans.push_back(node);
        for(auto i:adj[node]){
            if(!vis[i]){
                vis[i]=1;
                q.push(i);
            }
        }
    }
    return ans;
}