/in/foo.cc: In function 'int main()':
/in/foo.cc:65:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j = 0;j<v[i].size();j++)huan[v[i][j]]=1;
                  ~^~~~~~~~~~~~
/in/foo.cc:72:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j = 0;j<v[i].size();j++)huan[v[i][j]]=1;
                   ~^~~~~~~~~~~~