foo.cc: In function 'int main(int, char**)':
foo.cc:23:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |   for(int i = 0; i < ans.size(); i++) {
      |                  ~~^~~~~~~~~~~~

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