Compilare: user.cpp: In function ‘void dfs(int, int, int, int)’: user.cpp:20:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < adj[x].size(); i++) { ^ user.cpp:21:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = i + 1; j < adj[x].size(); j++) { ^ user.cpp: In function ‘int main()’: user.cpp:41:15: warning: unused variable ‘j’ [-Wunused-variable] int n, i, j, a, b; ^