fork download 
  1. #include <iostream>
  2. #include <set>
  3. #include <vector>
  4.  
  5. std::vector<std::pair<int, int>> find_sums(const std::set<int>&s, int total)
  6. {
  7. 	if (s.empty()) {
  8. 		return {};
  9. 	}
  10. 	auto b = s.begin();
  11. 	auto e = s.end();
  12. 	--e;
  13.  
  14. 	std::vector<std::pair<int, int>> res;
  15. 	do {
  16. 		auto sum = *b + *e;
  17. 		if (sum == total) {
  18. 			res.push_back({*b, *e});
  19. 			++b;
  20. 		} else if (sum < total) {
  21. 			++b;
  22. 		} else { // sum > total
  23.             if (e == s.begin()) {
  24.             	break;
  25.             }
  26.             --e;
  27. 		}
  28.  
  29. 	} while (b != e);
  30.  
  31. 	return res;
  32. }
  33.  
  34. void print(const std::vector<std::pair<int, int>>& pairs)
  35. {
  36. 	for (const auto& p : pairs) {
  37. 		std::cout << "{" << p.first << ", " << p.second << "} ";
  38. 	}
  39. 	std::cout << std::endl;
  40. }
  41.  
  42.  
  43. int main() {
  44. 	print(find_sums({1, 3, 5, 7, 11, 20}, 10)); // {3, 7}
  45. 	print(find_sums({1, 3, 5, 7, 11, 20}, 12)); // {1, 11}, {5, 7}
  46. }
Success #stdin #stdout 0s 3460KB
comments (?)
stdin 
Standard input is empty
stdout 
{3, 7} 
{1, 11} {5, 7}
https://ideone.com/GgiOsG
language:
C++14 (gcc 8.3)
created:
9 years 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!