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  1. #include <iostream>
  2. #include <vector>
  3.  
  4. enum class Op
  5. {
  6. 	ADD,
  7. 	SUB
  8. };
  9.  
  10. int evaluate(std::vector<int> numbers, std::vector<Op> operations, std::string & formula)
  11. {
  12. 	formula = std::to_string(numbers[0]);
  13. 	int total = numbers[0];
  14. 	for(int i = 0 ; i < operations.size() ; ++i)
  15. 	{
  16. 		if(operations[i] == Op::ADD) 
  17. 		{
  18. 			formula += "+" + std::to_string(numbers[i+1]);
  19. 			total += numbers[i+1];
  20. 		}
  21. 		else
  22. 		{
  23. 			formula += "-" + std::to_string(numbers[i+1]);
  24. 			total -= numbers[i+1];
  25. 		}
  26. 	}
  27.  
  28. 	return total;
  29. }
  30.  
  31. void generate(int level, std::vector<int> numbers, std::vector<Op> operations)
  32. {
  33. 	if(level == 10)
  34. 	{
  35. 		std::string formula;
  36. 		if(evaluate(numbers, operations, formula) == 100)
  37. 		{
  38. 			std::cout << formula << " = 100" << std::endl;
  39. 		}
  40.  
  41. 		return;
  42. 	}
  43.  
  44. 	auto numbers_next = numbers;
  45. 	numbers_next.push_back(level);
  46.  
  47. 	auto operations_add = operations;
  48. 	operations_add.push_back(Op::ADD);
  49. 	generate(level+1, numbers_next, operations_add);
  50.  
  51. 	auto operations_sub = operations;
  52. 	operations_sub.push_back(Op::SUB);
  53. 	generate(level+1, numbers_next, operations_sub);
  54.  
  55. 	auto numbers_num = numbers;	
  56. 	numbers_num.back() = numbers_num.back() * 10 + level;
  57. 	generate(level+1, numbers_num, operations);
  58. }
  59.  
  60. int main()
  61. {
  62. 	generate(2, {1}, {});
  63. }
  64.  
Success #stdin #stdout 0.02s 3236KB
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stdin
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Standard input is empty
stdout
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1+2+3-4+5+6+78+9 = 100
1+2+34-5+67-8+9 = 100
1+23-4+5+6+78-9 = 100
1+23-4+56+7+8+9 = 100
12+3+4+5-6-7+89 = 100
12+3-4+5+67+8+9 = 100
12-3-4+5-6+7+89 = 100
123+4-5+67-89 = 100
123+45-67+8-9 = 100
123-4-5-6-7+8-9 = 100
123-45-67+89 = 100
https://ideone.com/Pnb6NW
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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