Compilare: user.cpp: In function ‘void solve()’: user.cpp:9:11: warning: unused variable ‘first’ [-Wunused-variable] #define f first ^ user.cpp:97:25: note: in expansion of macro ‘f’ int i, j, K = k, x, f = 1; ^ user.cpp: In function ‘void read()’: user.cpp:18:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cabane.in", "r", stdin); ^ user.cpp:19:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &k); ^ user.cpp: In function ‘void write()’: user.cpp:128:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cabane.out", "w", stdout); ^