foo.cc: In function 'int dfs(int, int)':
foo.cc:21:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<outt[now].size();i++)
               ~^~~~~~~~~~~~~~~~~
foo.cc: In function 'int work()':
foo.cc:85:26: warning: format '%d' expects argument of type 'int', but argument 2 has type 'std::vector<int>::size_type {aka long unsigned int}' [-Wformat=]
  printf("%d\n",ans.size());
                ~~~~~~~~~~^
foo.cc:86:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0;i<ans.size();i++) printf("%d\n",ans[i]);
               ~^~~~~~~~~~~
foo.cc:55:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d",&n,&m,&sa,&sb);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:61:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&x);
   ~~~~~^~~~~~~~~
foo.cc:67:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&x);
   ~~~~~^~~~~~~~~
foo.cc:74:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~

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

正在同步测试数据，请稍后
{"receive":"2020-07-27T12:04:27.106Z","handle":"2020-07-27T12:04:27.106Z","cache_start":"2020-07-27T12:04:27.112Z","read_cases":"2020-07-27T12:04:28.942Z","judge":"2020-07-27T12:04:28.942Z","done":"2020-07-27T12:04:30.264Z"}