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  1. #include <bits/stdc++.h>
  2. #define ll long long
  3.  
  4. using namespace std;
  5.  
  6. bool isPrime(int n)
  7. {
  8.     if(n == 2)
  9.         return true;
  10.     if(n < 2 || (n > 2 && !(n&1)))
  11.         return false;
  12.     int i = 3;
  13.     for(; i*i <= n ; i+=2)
  14.         if(n%i == 0)
  15.             return false;
  16.     return true;
  17.  
  18. }
  19.  
  20.  
  21. void solve()
  22. {
  23.     int n,m;cin>>n>>m;
  24.     vector<vector<int>> v(n,vector<int>(m));
  25.     for(auto& row : v)
  26.         for(auto& col : row)
  27.             cin>>col;
  28.  
  29.     int ans = LONG_MAX;
  30.     for(int j = 0 ; j < n ; j++)
  31.         {
  32.             int sum = 0;
  33.             for(int i = 0 ; i < m ; i++)
  34.                 {
  35.                     int Tsum = 0;
  36.                     while(!isPrime(v[j][i]))
  37.                         v[j][i]++,sum++,Tsum++;
  38.                     v[j][i]-= Tsum;
  39.                 }
  40.             ans = min(ans,sum);
  41.         }
  42.  
  43.     for(int j = 0 ; j < m ; j++)
  44.         {
  45.             int sum = 0;
  46.             for(int i = 0 ; i < n ; i++)
  47.                 {
  48.                     int Tsum = 0;
  49.                     while(!isPrime(v[i][j]))
  50.                         v[i][j]++,sum++,Tsum++;
  51.                     v[i][j] -= Tsum;
  52.                 }
  53.             ans = min(ans,sum);
  54.         }
  55.  
  56.     cout << ans << endl;
  57.  
  58. }
  59.  
  60. int main()
  61. {
  62. //    int t;cin>>t;
  63. //    while(t--)
  64.         solve();
  65.     return 0;
  66. }
Success #stdin #stdout 0.01s 5280KB
comments (?)
stdin 
3 3
1 2 3
5 6 1
4 4 1
stdout 
-1
https://ideone.com/J7ojlQ
language:
C++ (gcc 8.3)
created:
14 days ago
visibility:
public

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