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  1. #include <iostream>
  2. using namespace std;
  3. typedef long long ll;
  4. const ll INF = 3e2+5;
  5. ll arr[INF][INF];
  6. void power(ll n){
  7. 	ll arr1[n][n];
  8. 	for(int i  = 0 ; i < n ; i++){
  9. 		for(int j = 0 ; j < n; j++){
  10. 			arr1[i][j]=0;
  11. 			for(int k = 0 ; k < n ; k ++){
  12. 				arr1[i][j]+=arr[i][k]* arr[k][j];
  13. 			}
  14.  
  15. 		}
  16. 	}
  17. 	for(int i  = 0 ; i < n ; i++){
  18. 		for(int j = 0 ; j < n; j++){
  19. 			arr[i][j]=arr1[i][j];
  20. 		}
  21. 	}
  22. }
  23. int main() {
  24. 	ios_base::sync_with_stdio(0);
  25. 	cin.tie(0);
  26. 	int n,m ;
  27. 	cin>>n>>m;
  28. 	ll a,b;
  29. 	for(int i = 0 ; i < m ; i++){
  30. 		cin>>a>>b;
  31. 		a--;
  32. 		b--;
  33. 		if(a!=b){
  34. 			arr[a][b]++;
  35. 			arr[b][a]++;	
  36. 		}
  37. 	}
  38. 	power(n);
  39. 	ll to_del[n];
  40. 	for(int i = 0 ; i < n; i++){
  41. 		to_del[i]=0;
  42. 		for(int j = 0 ; j < n; j++){
  43. 			if(i==j){
  44. 				arr[i][i] = 0;
  45. 			}else{
  46. 				to_del[i]+=arr[i][j];
  47. 			}
  48. 		}
  49. 	}
  50. 	power(n);
  51. 	ll answer =0;
  52. 	for(int i = 0 ; i < n ; i++){
  53. 		answer +=arr[i][i]-to_del[i];
  54. 	}
  55. 	cout<<answer/8;
  56. 	return 0;
  57. }
Success #stdin #stdout 0s 15960KB
comments (?)
stdin
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5 7
1 3
1 4
2 4
2 5
3 4
3 5
4 5
stdout
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2
https://ideone.com/GJPNVb
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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