队列算法

1.优先队列算法

mysql的排序如果limit比拟小的话会应用优先队列算法。如果limit比拟大采纳的是归并排序算法。
实现:

public class PriorityQueue<E> {
    private BinaryHeap<E> heap;
    
    public PriorityQueue(Comparator<E> comparator) {
        heap = new BinaryHeap<>(comparator);
    }
    
    public PriorityQueue() {
        this(null);
    }
    
    public int size() {
        return heap.size();
    }

    public boolean isEmpty() {
        return heap.isEmpty();
    }
    
    public void clear() {
        heap.clear();
    }

    public void enQueue(E element) {
        heap.add(element);
    }

    public E deQueue() {
        return heap.remove();
    }

    public E front() {
        return heap.get();
    }
}