Compilare: user.cpp: In function ‘int Union(int, int)’: user.cpp:75:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘void kruskal(int, int)’: user.cpp:134:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0 ; i < min_span.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:185:9: warning: unused variable ‘i’ [-Wunused-variable] int i; ^