art.cpp: In function 'int main()':
art.cpp:31:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
31 | for (int i = 0; i < a.size(); i++) {
| ~~^~~~~~~~~~
art.cpp:36:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
36 | for (int i = 0; i < a.size(); i++) {
| ~~^~~~~~~~~~
art.cpp:38:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
38 | for (int j = i + 1; j < a.size(); j++) {
| ~~^~~~~~~~~~