Compilare: user.cpp: In function ‘int main()’: user.cpp:32:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0, j = 0; i < to_give.size() && j < to_recv.size();) { ^ user.cpp:32:64: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0, j = 0; i < to_give.size() && j < to_recv.size();) { ^ user.cpp:48:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < edges.size(); ++i) { ^