Compilare: user.cpp: In function ‘void Dfs(int, int)’: user.cpp:17:9: warning: unused variable ‘cnt’ [-Wunused-variable] int cnt = father == 0 ? 0: 1; ^ user.cpp: In function ‘int main()’: user.cpp:44:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("something.in", "r", stdin); ^ user.cpp:45:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("something.out", "w", stdout); ^ user.cpp:48:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &N, &M); ^ user.cpp:57:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^