View Compilation Error

0_0_23750689_851.cpp: In function 'int main()':
0_0_23750689_851.cpp:48:29: error: 'r' was not declared in this scope
                 int t = min(r[i][j], c[i][j]);
                             ^
0_0_23750689_851.cpp:53:21: error: 'sum' was not declared in this scope
                     sum = f[i + 1][j + 1] - f[i + k - 1][j + 1] - f[i + 1][j + k - 1] + f[i + k - 1][j + k - 1];
                     ^