foo.cc: In function 'void dfs(int, int)':
foo.cc:10:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0; i<t[x].size(); i++)
                ~^~~~~~~~~~~~
foo.cc: In function 'void hsh(int, int, int, int)':
foo.cc:20:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0; i<t[x].size(); i++)
                ~^~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:61:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j=0; j<cnt[i].size()-1; j++) cout<<cnt[i][j]<<"=";
                  ~^~~~~~~~~~~~~~~~

自豪的采用 HydroJudge 进行评测(github.com/hydro-dev/HydroJudge)

{"receive":"2020-07-21T11:43:35.194Z","handle":"2020-07-21T11:43:35.195Z","cache_start":"2020-07-21T11:43:35.201Z","read_cases":"2020-07-21T11:43:35.327Z","judge":"2020-07-21T11:43:35.328Z","done":"2020-07-21T11:43:36.520Z"}