Compilare: user.cpp: In function ‘int main()’: user.cpp:32:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("arbsat2.in", "r", stdin); ^ user.cpp:33:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("arbsat2.out", "w", stdout); ^ user.cpp:35:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &n, &m); ^ user.cpp:37:46: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d", &A[i].first, &A[i].second); ^ user.cpp: In function ‘void solve(int, int)’: user.cpp:27:26: warning: ‘ultima’ may be used uninitialized in this function [-Wmaybe-uninitialized] solve (ultima + 1, dr); ^