Compilare: user.cpp: In function ‘void union1(int, int)’: user.cpp:37:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<mult[x].size(); i++) { ^ user.cpp:42:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<mult[y].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:73:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < sol.size() - 1; i += 2) { ^