/in/foo.cc: In function 'int main()':
/in/foo.cc:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < A[0].size(); i++)
                  ~~^~~~~~~~~~~~~
/in/foo.cc:22:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < A.size(); k++)
                    ~~^~~~~~~~~~
/in/foo.cc:27:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int q = 0; q < A.size() && dd == 0; q++)//x
                     ~~^~~~~~~~~~
/in/foo.cc:45:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int q = 0; q < A[0][0].size() && dd == 0; q++)//z
                     ~~^~~~~~~~~~~~~~~~
/in/foo.cc:63:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int q = 0; q < A[0].size() && dd == 0; q++)//y
                     ~~^~~~~~~~~~~~~
/in/foo.cc:86:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < A[0].size(); i++)
                  ~~^~~~~~~~~~~~~
/in/foo.cc:90:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < A.size(); k++)
                    ~~^~~~~~~~~~