Submission #3418035

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Source Code Expand

#include <iostream>
#include <string>
#include <vector>

using namespace std;

bool dfs(int d, vector<int>& num, int result, string exp)
{
  if (d == num.size()) {
    if (result == 7) {
      cout << exp << "=7" << endl;
      return true;
    }
    return false;
  }

  if (dfs(d + 1, num, result + num[d], exp + '+' + to_string(num[d])))
    return true;
  if (dfs(d + 1, num, result - num[d], exp + '-' + to_string(num[d])))
    return true;
  return false;
}

int main()
{
  vector<int> num(4);
  for (int i = 0; i < 4; i++) {
    cin >> num[i];
  }
  dfs(1, num, num[0], to_string(num[0]));

  return 0;
}

Submission Info

Judge Result