Submission #2236772

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Source Code Expand

#include <iostream>
#include <math.h>
#include <string>
#include <stack>
using namespace std;

int ctoi(const char c){
  if('0' <= c && c <= '9') return (c-'0');
  return -1;
}

int main(void) {
  stack<int> st;
  
	cin.tie(0);
  ios::sync_with_stdio(false);
  
  //ABCDを取得
  string S;
  cin >> S;
  int A = ctoi(S[0]);
  int B = ctoi(S[1]);
  int C = ctoi(S[2]);
  int D = ctoi(S[3]);
  
  string ope[3];
  for (int i=0 ; i<8 ; i++) {
    st.push(D);
    st.push(C);
    st.push(B);
    st.push(A);
    
    for (int j=0 ; j<3 ; j++) {
      ope[j] = ((i>>j) % 2) == 1 ? "+" : "-" ;
      
      int left = st.top();
      st.pop();
      int right = st.top();
      st.pop();
      if (ope[j] == "+") {
        st.push(left + right);
      } else {
        st.push(left - right);
      }
    }  
    
    if (st.top() == 7) {
      break;
    }
    
    st.pop();
  }
  
  cout << A << ope[0] << B << ope[1] << C << ope[2] << D << "=7" << "\n";
}

Submission Info

Judge Result