foo.cc: In function 'int main()':
foo.cc:30:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < G[u].size(); i++) {
                           ^

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

{"receive":"2020-04-28T05:57:31.217Z","handle":"2020-04-28T05:57:31.217Z","cache_start":"2020-04-28T05:57:31.225Z","read_cases":"2020-04-28T05:57:33.937Z","judge":"2020-04-28T05:57:33.937Z","done":"2020-04-28T05:57:35.117Z"}