Compilare: user.cpp: In function ‘int dfs(int)’: user.cpp:19:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1; i<=a[nod].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:31:18: warning: unused variable ‘c’ [-Wunused-variable] int n, x, y,c, k=0; ^ user.cpp: In function ‘int dfs(int)’: user.cpp:28:1: warning: control reaches end of non-void function [-Wreturn-type] } ^