foo.cc: In function 'void cal_deep(int, int)':
foo.cc:12:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |      for(int i=0;i<p[x].size();i++)
      |                  ~^~~~~~~~~~~~
foo.cc: In function 'int remove(int, int)':
foo.cc:21:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |    for(int i=0;i<p[x].size();i++)
      |                ~^~~~~~~~~~~~
foo.cc: In function 'void dfs(int, int)':
foo.cc:30:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |     for(int i=0;i<q[layer].size();i++)
      |                 ~^~~~~~~~~~~~~~~~

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