foo.cc: In function 'void dfs(int)':
foo.cc:39:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   39 |     for (int j = 0;j < a[i].size();j++)
      |                    ~~^~~~~~~~~~~~~
foo.cc:138:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::__cxx11::basic_string<char> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  138 |     for (int j = 0;j < a[path[i]].size();j++)
      |                    ~~^~~~~~~~~~~~~~~~~~~

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