C. Chessboard（ Educational Codeforces Round 41 (Rated for Div. 2)）

 //暴力
 #include <iostream>
 #include <algorithm>
 #include <string>

 using namespace std;
 const int N = ;
 string s1[N], s2[N], s3[N], s4[N];
 int a[N][N], b[N][N];

 int main()
 {
     int n;
     cin >> n;
     for (int i = ; i<n; i++)
         cin >> s1[i];
     cin.get();
     for (int i = ; i<n; i++)
         cin >> s2[i];
     cin.get();
     for (int i = ; i<n; i++)
         cin >> s3[i];
     cin.get();
     for (int i = ; i<n; i++)
         cin >> s4[i];

     for (int i = ; i<n; i++)
     for (int j = ; j < n; j++){
         //只有两种方式
         a[i][j] = (i + j) %  ==  ?  : ;
         b[i][j] = (i + j) %  ?  : ;
     }
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         a[i][j] += , b[i][j] += ;

     //比较
     int ans = 1e9;
     int f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != a[i][j]) + (s2[i][j] != a[i][j]) + (s3[i][j] != b[i][j]) + (s4[i][j] != b[i][j]);
     ans = min(ans, f);
     f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != a[i][j]) + (s2[i][j] != b[i][j]) + (s3[i][j] != a[i][j]) + (s4[i][j] != b[i][j]);
     ans = min(ans, f);
     f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != a[i][j]) + (s2[i][j] != b[i][j]) + (s3[i][j] != b[i][j]) + (s4[i][j] != a[i][j]);
     ans = min(ans, f);
     f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != b[i][j]) + (s2[i][j] != a[i][j]) + (s3[i][j] != a[i][j]) + (s4[i][j] != b[i][j]);
     ans = min(ans, f);
     f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != b[i][j]) + (s2[i][j] != a[i][j]) + (s3[i][j] != b[i][j]) + (s4[i][j] != a[i][j]);
     ans = min(ans, f);
     f = ;
     for (int i = ; i<n; i++)
     for (int j = ; j<n; j++)
         f += (s1[i][j] != b[i][j]) + (s2[i][j] != b[i][j]) + (s3[i][j] != a[i][j]) + (s4[i][j] != a[i][j]);
     ans = min(ans, f);
     cout<< ans <<endl;
     system("pause");
     return ;
 }