Compilare: main.cpp: In function 'void dfs(int)': main.cpp:14:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[nod].size(); i++){ ~^~~~~~~~~~~~~~ main.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<a[nod].size(); i++){ ~^~~~~~~~~~~~~~