Compilare: main.cpp: In function 'void dfs(int, int)': main.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[nod].size(); i++){ ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:57:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0; i<a[nod].size(); i++){ ~^~~~~~~~~~~~~~