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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. int main() {
  5. 	int n,m;
  6. 	cin>>n>>m;
  7. 	int ms[n][n]={};
  8. 	for(int i=0; i<m; i++){
  9. 		int a,b;
  10. 		cin>>a>>b;
  11. 		a--; b--;
  12. 		ms[a][b]=1;
  13.  
  14. 	}
  15. 	string s="YES";
  16. 	for(int i=0; i<n; i++){
  17. 		for(int j=0; j<n; j++){
  18. 			if(ms[i][j]+ms[j][i]!=1) s="NO";
  19. 		}
  20. 	}
  21. 	cout<<s;
  22. 	return 0;
  23. }
Success #stdin #stdout 0.01s 5308KB
comments (?)
stdin 
5 10
1 2
1 3
1 5
2 3
2 5
4 1
4 2
4 3
4 5
5 3
stdout 
NO
https://ideone.com/8ahXQC
language:
C++ (gcc 8.3)
created:
14 days ago
visibility:
public

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