/in/foo.cc: In function 'int main()':
/in/foo.cc:22:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < str.size(); i++)
                    ^
/in/foo.cc:24:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (poker[i] + 1 == conv(str[i].front()) || conv(str[i].back()) == poker[i] - 1) ans.push_back(true);
                    ^
/in/foo.cc:24:67: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (poker[i] + 1 == conv(str[i].front()) || conv(str[i].back()) == poker[i] - 1) ans.push_back(true);
                                                                   ^
/in/foo.cc:28:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ans.size(); i++)
                    ^