Compilare: main.cpp: In member function 'double Graph::prims_algorithm(int)': main.cpp:34:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 34 | for (int i = 0; i < nodes_positions.size(); ++i) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:40:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 40 | for (int j = 0; j < nodes_positions.size(); ++j) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:53:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 53 | for (int j = 0; j < nodes_positions.size(); ++j) | ~~^~~~~~~~~~~~~~~~~~~~~~~~