foo.cc: In function 'void solve()':
foo.cc:46:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   46 |         for (int i = 0; i < sub2.size(); i++)
      |                         ~~^~~~~~~~~~~~~
foo.cc:47:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   47 |                 for (int j = 0; j < sub1.size(); j++)
      |                                 ~~^~~~~~~~~~~~~
foo.cc:54:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   54 |         for (int i = 0; i < sub2.size(); i++)
      |                         ~~^~~~~~~~~~~~~
foo.cc:57:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |                 for (int j = 0; j < sub1.size(); j++)
      |                                 ~~^~~~~~~~~~~~~

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