fork download
copy 
  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5. 	// your code goes here
  6. 	int n,d;
  7. 	cin>>n>>d;
  8.  
  9. 	vector<int> v(n);
  10. 	for(int i = 0; i < n; i++){
  11. 		cin>>v[i];
  12. 	}
  13.  
  14. 	unordered_map<int,int> ump;
  15. 	int cnt = 0;
  16.  
  17. 	for(int k = 0; k < n; k++){
  18.  
  19. 		// Sometimes v[k] is greater then k then if we did not perform this step which 
  20. 		// leads to end up -ve numbers
  21.  
  22. 		int ele = v[k] % d;
  23.  
  24. 		int rem = (d - ele) % d;
  25.  
  26. 		if(ump.count(rem)){
  27. 			cnt += ump[rem];
  28. 		}
  29.  
  30. 		// ump[v[i] % d] ++;
  31. 		for(int u = 0; u <= k-1; u++){
  32. 			ump[(v[u] + v[k]) % d]++;
  33. 		}
  34. 	}
  35. 	cout<<cnt<<endl;
  36. 	return 0;
  37. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin
copy 
6 5
2 2 5 5 3 3
stdout
copy 
8
https://ideone.com/D8M41m
language:
C++14 (gcc 8.3)
created:
1 hour ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!