Compilare: main.cpp: In member function 'double Graph::prims_algorithm()': main.cpp:36:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 36 | for (int j = 1; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:41:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 41 | for (int i = 1; i < nodes_positions.size(); i++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:47:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 47 | for (int j = 0; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~ main.cpp:60:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare] 60 | for (int j = 0; j < nodes_positions.size(); j++) | ~~^~~~~~~~~~~~~~~~~~~~~~~~