foo.cc: In function 'int main()':
foo.cc:53:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |   for (int i = 0; i < a[d].size(); i++) {
      |                   ~~^~~~~~~~~~~~~
foo.cc:64:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |   for (int j = 0; j < a[u = tp[i]].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:76:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |   for (int j = 0; j < a[u = tp[i]].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~~~~~
foo.cc:84:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   84 |   for (int j = 0; j < a[tp[i]].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~~

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