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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main(){
  5. 	int count = 0;
  6. 	int n,x;
  7. 	cin >> n >> x;
  8. 	int A[n];
  9. 	for (int i = 0; i < n; i++){
  10. 		cin >> A[i];
  11. 	}
  12. 	sort(A, A + n);
  13. 	int f = 0;
  14. 	int e = n -1;
  15. 	//for (int i = 0; i < n; i++){
  16. 	//	cout << A[i];
  17. 	//}
  18. 	while (e >= f + 1){
  19. 		if (A[f] + A[e] == x){
  20. 			count++;
  21. 			//cout << A[f] << " " << A[e] << "/";
  22. 			if (A[e] == A[e - 1] and e != f){
  23. 				e--;
  24. 			}
  25. 			else if (A[f] == A[f + 1]and f != e){
  26. 				f++;
  27. 			}
  28. 			else{
  29. 				f++;
  30. 			}
  31. 		}
  32. 		else if (A[f] + A[e] > x){
  33. 			e--;
  34. 		}
  35. 		else{
  36. 			f++;
  37. 		}
  38. 	}
  39. 	cout << count;
  40. }
  41.  
Success #stdin #stdout 0s 5300KB
comments (?)
stdin
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7 6
1 2 4 3 4 5 3
stdout
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4
https://ideone.com/FmY9vl
language:
C++14 (gcc 8.3)
created:
3 hours ago
visibility:
public

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