/in/foo.cc: In function 'void solve()':
/in/foo.cc:153:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 0;j<s.size();j++)
                  ~^~~~~~~~~
/in/foo.cc:222:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0;i<nums.size();i++)
                  ~^~~~~~~~~~~~