Compilare: main.cpp: In member function 'double Graph::prims_algorithm()': main.cpp:37:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 37 | for (int j=1; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:44:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 44 | for (int i = 1; i < nodes_positions.size(); i++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:50:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 50 | for (int j = 0; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:63:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 63 | for (int j = 0; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~