postmen.cpp: In function 'int main()':
postmen.cpp:56:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
56 | for(int i=0; i<P.size(); i++)
| ~^~~~~~~~~
postmen.cpp:63:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
63 | for(int i=0; i<A.size(); i++)
| ~^~~~~~~~~
postmen.cpp:65:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
65 | for(int j=0; j<A[i].size(); j++)
| ~^~~~~~~~~~~~