通过堆实现一个优先队列，

//最大堆，数组实现完全二叉堆
public class MaxHeap {
int[] data;// data[0]为最大堆的数量
int capacity;//最大堆的容量

public MaxHeap(int capacity) {    this.capacity = capacity;    data = new int[capacity + 1];    data[0] = 0;}//heapfiypublic MaxHeap(int[] arr) {    this.capacity = arr.length;    data = new int[arr.length + 1];    data[0] = arr.length;    for (int i = 0; i < arr.length; i++)        data[i + 1] = arr[i];}public static void main(String[] args) {    MaxHeap heap = new MaxHeap(10);    int size = heap.size();    boolean bool = heap.isEmpty();    heap.insert(15);    heap.insert(12);    heap.insert(11);    heap.insert(16);    for (int j = 1; j <= heap.data[0]; j++)        System.out.println(heap.data[j]);    int max = heap.extractMax();    for (int j = 1; j <= heap.data[0]; j++)        System.out.println(heap.data[j]);}public int extractMax() {    if (data[0] > 0) {        int max = data[1];        data[1] = data[data[0]];        data[0]--;        shiftDown(1);        return max;    }    return Integer.MAX_VALUE;}public void shiftDown(int i) {    while (i * 2 <= data[0]) {        int j = i * 2;        if (j + 1 <= data[0])            if (data[j + 1] > data[j])                j += 1;        if (data[i] < data[j]) {            swap(i, j);            i = j;        } else            break;    }}public void insert(int i) {    if (capacity >= data[0] + 1) {        data[++data[0]] = i;        shiftUp(data[0]);    }}private void shiftUp(int i) {    while (i > 1 && data[i / 2] < data[i]) {        swap(i / 2, i);        i /= 2;    }}private void swap(int i, int j) {    data[i] = data[i] ^ data[j];    data[j] = data[i] ^ data[j];    data[i] = data[i] ^ data[j];}public boolean isEmpty() {    return data[0] == 0;}public int size() {    return data[0];}

}