Compilare: main.cpp: In function 'void build(int, int, int)': main.cpp:39:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<aint[nod].v.size();i++){ ~^~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:145:20: warning: 'sol' may be used uninitialized in this function [-Wmaybe-uninitialized] fout<<sol<<"\n"; ^~~~