foo.cc: In function 'int bfs_1(int, int, int*, int*)':
foo.cc:59:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |         for (int i=0;i<cw[now].size();i++)
      |                      ~^~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:99:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |         for (int i=0;i<cw.size();i++)
      |                      ~^~~~~~~~~~
foo.cc:109:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  109 |             scanf("%d",&a[i]);
      |             ~~~~~^~~~~~~~~~~~
foo.cc:113:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  113 |             scanf("%d%d%d",&a,&b,&c);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~

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