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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. const int N = 100000;
  5. int tr[101010];
  6. void add(int pos, int val) {
  7. 	for (int i = pos; i <= N; i |= (i + 1)) {
  8. 		tr[i] += val;		
  9. 	}
  10. }
  11. int sum(int pos) {
  12. 	int res = 0;
  13. 	for (int i = pos; i >= 0; i = (i&(i + 1)) - 1) {
  14. 		res += tr[i];	
  15. 	}
  16. 	return res;
  17. }
  18.  
  19. int main() {
  20. 	// your code goes here
  21. 	add(0, 5);
  22. 	add(7, 10);
  23. 	cout << sum(0) << ' ' << sum(7) << ' ' << sum(100) << endl;
  24. 	return 0;
  25. }
Success #stdin #stdout 0s 3860KB
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5 15 15
https://ideone.com/8k2jMb
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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