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  1. #include <iostream>
  2. using namespace std;
  3. #include<bits/stdc++.h>
  4. //graph bfs
  5. int main() {
  6. 	// your code goes here
  7. 	int n ; int m ; 
  8. 	cin>>n>>m;
  9. 	vector<vector<int>>adj(n+1);
  10.     vector<bool>vis(n+1,false);
  11.     int level[n+1];
  12. 	for(int i = 0 ; i < m ; i++){
  13. 		int u ; int v ; 
  14. 		cin>>u>>v; 
  15. 		adj[u].push_back(v);
  16. 		adj[v].push_back(u);
  17. 	}
  18. 	queue<int>q;
  19. 	int src = 2 ;
  20.     q.push(2);
  21.     vis[src]=true;
  22.     level[src]=0;
  23. 	while(!q.empty()){
  24. 		int curr = q.front();
  25. 		q.pop();
  26. 		cout<<curr<<" level is "<<level[curr]<<endl;
  27. 		for(auto adjacent : adj[curr]){
  28. 			if(!vis[adjacent]){
  29. 				vis[adjacent]= true;
  30. 				q.push(adjacent);
  31. 				level[adjacent]=level[curr]+1;
  32. 			}
  33. 		}
  34.  
  35. 	}
  36.  
  37.  
  38.  
  39. 	return 0;
  40. }
Success #stdin #stdout 0s 5316KB
comments (?)
stdin
copy 
8 9 
2 8 
4 8 
4 3
2 4
4 5
5 1 
1 7
3 7 
3 6
stdout
copy 
2 level is 0
8 level is 1
4 level is 1
3 level is 2
5 level is 2
7 level is 3
6 level is 3
1 level is 3
https://ideone.com/5jByuo
language:
C++ (gcc 8.3)
created:
6 hours ago
visibility:
public

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