PriorityQueue简单实现

ackage PriorityQueue;
 
import java.util.Arrays;
 
/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: czt20
 * Date: 2026 -01-15
 * Time: 21:06
 */
public class PriorityQueue {
    public int[] elm;
    public int usdesize = 0;
 
    public PriorityQueue() {
        this.elm = new int[10];
    }
 
    public void input(int[] arr) {
        for (int i = 0; i < arr.length; i++) {
            elm[i] = arr[i];
            this.usdesize++;
        }
    }
 
    public void creatHeap() {
        for (int p = (this.usdesize - 1 - 1) / 2; p >= 0; p--) {
            shiftDown(p, this.usdesize);
        }
    }
 
    //大根堆
    private void shiftDown(int p, int usdesize) {
        int child = 2 * p + 1;
        while (child < usdesize) {
            if (child + 1 < usdesize && elm[child] < elm[child + 1]) {
                child++;
            }
            if (elm[child] > elm[p]) {
                int temp = elm[child];
                elm[child] = elm[p];
                elm[p] = temp;
                p = child;
                child = 2 * p + 1;
            } else {
                break;
            }
        }
    }
 
    public void h() {
        for (int i = 0; i < elm.length; i++) {
           if (elm[i]!=0){
               System.out.println(elm[i]);
           }
 
        }
    }
 
    public void push(int val) {
 
        if (isFull()) {
         elm= Arrays.copyOf(elm,2*elm.length);
        }
        elm[usdesize] = val;
        shiftup(usdesize);
        usdesize++;
    }
 
    private boolean isFull() {
        return usdesize== elm.length;
    }
    //小根堆
    private void shiftup(int child) {
        int parent = (child - 1) / 2;
        while (parent >= 0) {
            if (elm[child] < elm[child + 1]) {
                child++;
            }
            if (elm[child] > elm[parent]) {
                int temp = elm[child];
                elm[child] = elm[parent];
                elm[parent] = temp;
                child = parent;
                parent = (child - 1) / 2;
            } else {
                break;
            }
 
 
        }
 
    }
    //插入
   public int poll(int index){
        if(index>usdesize-1){
            return -1;
        }
        int val=elm[index];
        int temp=elm[index];
        elm[index]=elm[usdesize-1];
        elm[usdesize-1]=temp;
        shiftDown(0,usdesize-1);
        usdesize--;
          return  elm[index];
   }
   public int findMaxki(){
 
   }
}