foo.cc: In function 'void work_1(int)':
foo.cc:31:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |     for (int i=0;i<s[now].size();i++)
      |                  ~^~~~~~~~~~~~~~
foo.cc: In function 'void work_2(int)':
foo.cc:63:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     for (int i=0;i<s[now].size();i++)
      |                  ~^~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:77:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   77 |             scanf("%d%d",&x,&y);
      |             ~~~~~^~~~~~~~~~~~~~

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