foo.cc: In function 'int bfs_1(int, int)':
foo.cc:36:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |         for (int i=1;i<c.size();i++)
      |                      ~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:78:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |         for (int i=0;i<c.size();i++)
      |                      ~^~~~~~~~~
foo.cc:71:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   71 |             scanf("%c",&c);
      |             ~~~~~^~~~~~~~~
foo.cc:72:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   72 |             scanf("%c%d",&c,&y);
      |             ~~~~~^~~~~~~~~~~~~~

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