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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. typedef long long int ll;
  6.  
  7. vector<ll> finals, curr;
  8.  
  9. ll n, val[36], tar;
  10.  
  11. void foo(int pos){
  12.     if(pos == n-1){
  13.         /*for(int j = 0; j < curr.size(); j++)
  14.             cout << curr[j] << " ";
  15.         cout << endl;*/
  16.         int counts = 0;
  17.         for(int j = 0; j < (2*n - 1); j++){
  18.             if(j % 2 != 0 && curr[j] == -3){
  19.                 val[counts - 1] *= curr[j+1];
  20.                 j++;
  21.                 continue;
  22.             }
  23.             if(j % 2 != 0 && curr[j] == -4){
  24.                 if(curr[j+1] == 0) return;
  25.                 if(val[counts - 1] % curr[j+1] != 0) return;
  26.                 val[counts - 1] /= curr[j+1];
  27.                 j++;
  28.                 continue;
  29.             }
  30.             val[counts++] = curr[j];
  31.         }
  32.  
  33.         ll ans = val[0];
  34.         for(int j = 1; j < counts; j += 2)
  35.             if(val[j] == -1) ans += val[j+1];
  36.             else ans -= val[j+1];
  37.  
  38.         //cout << ans << endl;
  39.  
  40.         if(ans == tar){
  41.             for(int j = 0; j < 2*n -1; j++)
  42.                 finals[j] = curr[j];
  43.             return;
  44.         }
  45.         return;
  46.     }
  47.  
  48.     curr[pos*2 + 1] = -1;
  49.     foo(pos+1);
  50.  
  51.     curr[pos*2+1] = -2;
  52.     foo(pos+1);
  53.  
  54.     curr[pos*2+1] = -3;
  55.     foo(pos+1);
  56.  
  57.     curr[pos*2+1] = -4;
  58.     foo(pos+1);
  59. }
  60.  
  61. int main(){
  62.     cin >> n;
  63.     while(n != -1){
  64.         curr.clear();
  65.         finals.clear();
  66.         cin >> tar;
  67.         for(int j = 0; j < n; j++){
  68.             ll t;
  69.             cin >> t;
  70.             curr.push_back(t);
  71.             curr.push_back(-1);
  72.             finals.push_back(t);
  73.             finals.push_back(-1);
  74.         }
  75.         foo(0);
  76.         cout << tar << " = ";
  77.         for(int j = 0; j < (2*n)-1; j++)
  78.             if(j%2 != 0 && finals[j] == -1) cout << "+ ";
  79.             else if(j%2 != 0 && finals[j] == -2) cout << "- ";
  80.             else if(j%2 != 0 && finals[j] == -3) cout << "* ";
  81.             else if(j%2 != 0 && finals[j] == -4) cout << "/ ";
  82.             else cout << finals[j] << " ";
  83.         cout << endl;
  84.         finals.clear();
  85.         cin >> n;
  86.     }
  87.     return 0;
  88. }
  89.  
Success #stdin #stdout 0s 16056KB
comments (?)
stdin
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4 16 2 2 2 2
3 9 2 3 3
3 21 1 4 5
-1
stdout
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16 = 2 * 2 * 2 * 2 
9 = 2 * 3 + 3 
21 = 1 + 4 * 5
https://ideone.com/vrUUHp
language:
C++14 (gcc 8.3)
created:
6 years ago
visibility:
public

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