rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:7:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
7 | for(int i1=1;i1<a.size()-1;i1++)
| ~~^~~~~~~~~~~
rect.cpp:8:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | for(int i2=i1;i2<a.size()-1;i2++)
| ~~^~~~~~~~~~~
rect.cpp:9:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
9 | for(int j1=1;j1<a[0].size()-1;j1++)
| ~~^~~~~~~~~~~~~~
rect.cpp:10:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
10 | for(int j2=j1;j2<a[0].size()-1;j2++){
| ~~^~~~~~~~~~~~~~