/in/foo.cc: In function 'int main()':
/in/foo.cc:19:53: warning: self-comparison always evaluates to true [-Wtautological-compare]
    if(f[i - 1][j] >= f[i - 1][j - 1] && f[i][j - 1] >= f[i][j - 1])
                                         ~~~~~~~~~~~~^~~~~~~~~~~~~~