堆/二叉排序树（Java）

package com.sort;

public class heapsort {
    public static void main(String[] args) {
        int[] a = {1, 4, 3, 5, 2, 7, 12, 45, 13, 754, 124, 754, 6, 32, 45, 1};
        heap(a);
        for (int b : a) System.out.println(b);
    }

    public static void heap(int[] a){
        for (int i = a.length/2; i >= 0; i--) {
            dfs(a,i,a.length);
        }
        int len = a.length;
        for (int i = a.length-1; i > 0 ; i--) {
            a[i] ^= a[0];
            a[0] ^= a[i];
            a[i] ^= a[0];
            len--;
            dfs(a,0,len);
        }
    }

    public static void dfs(int[] a ,int i,int len){
        int left = i*2 +1;
        int right = left + 1 ;
        int dad = i;
        if(left