Compilare: user.cpp: In function ‘void DFS(int, int, int, int)’: user.cpp:16:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < notempty[u1].size(); i++) { ^ user.cpp:18:31: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(auto x1: Gc[u1][cc]) { ^ user.cpp:20:35: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(auto x2: Gc[u2][cc]) ^ user.cpp: In function ‘int main()’: user.cpp:47:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] if(Gc[i][c[x]].empty()) ^ user.cpp:49:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] Gc[i][c[x]].push_back(x); ^ user.cpp:53:31: warning: array subscript has type ‘char’ [-Wchar-subscripts] for(auto x: Gc[i][c[i]]) ^ user.cpp:28:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.in", "r", stdin); ^ user.cpp:29:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbpal.out", "w", stdout); ^ user.cpp:33:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ user.cpp:35:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &x, &y); ^ user.cpp:41:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c ", &c[i]); ^