Compilare: user.cpp: In function ‘int main()’: user.cpp:18:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (pq.size() == k + 1) { ~~~~~~~~~~^~~~~~~~ user.cpp:6:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bleach.in", "r", stdin); ^ user.cpp:7:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bleach.out", "w", stdout); ^ user.cpp:10:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); ^ user.cpp:16:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^