/in/foo.cc: In function 'int main()':
/in/foo.cc:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<g[k].size();i++)
                     ~^~~~~~~~~~~~
/in/foo.cc:34:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int j=0;j<g[i].size();j++)
                         ~^~~~~~~~~~~~
/in/foo.cc:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<g[k].size();i++)
                     ~^~~~~~~~~~~~