Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<lst[nod].size();++i) ^ user.cpp: In function ‘bool check()’: user.cpp:40:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<lst[1].size();++i) ^ user.cpp: In function ‘void read()’: user.cpp:56:24: warning: ‘a’ may be used uninitialized in this function [-Wmaybe-uninitialized] lst[a].pb(b); ^