Compilare: user.cpp: In function ‘int main()’: user.cpp:36:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(tree_edges.size()<n-1) ^ user.cpp:38:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<edges.size();i++) ^ user.cpp:63:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<tree_edges.size();i++) ^ user.cpp:25:15: warning: unused variable ‘v1’ [-Wunused-variable] int n, m, v1, v2, i, cost=0; ^ user.cpp:25:19: warning: unused variable ‘v2’ [-Wunused-variable] int n, m, v1, v2, i, cost=0; ^