Compilare: user.cpp: In function ‘void back(int, int, int, int)’: user.cpp:28:17: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (pos > 1 && nr2 > ap[a[pos - 1]] || cnt == 0) return; ^ user.cpp: In function ‘int main()’: user.cpp:44:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("produse.in", "r", stdin); ^ user.cpp:45:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("produse.out", "w", stdout); ^ user.cpp:47:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &N, &D), mod = 1e9 + 7; ^ user.cpp:57:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &x), ap[x] ++; ^