堆排序宇宙最简单版本

package com.array;

import java.util.Arrays;

public class HeapSort {
    public static void main(String[] args) {
        int[] a = {45,14,5,24,5,62,7,84,34,14};
        buildHeap(a);

        System.out.println(Arrays.toString(a));
        heapSort(a);
        System.out.println(Arrays.toString(a));
    }
    public static void heapSort(int[] arr) {
        buildHeap(arr);
        for (int i = arr.length - 1; i >= 0; i--) {
            swap(arr, 0, i);
            heapfy(arr, 0, i-1);
        }
    }

    public static void buildHeap(int[] arr) {
        for (int i = arr.length / 2 - 1; i >= 0; i--) {
            heapfy(arr, i, arr.length - 1);
        }
    }

    public static void heapfy(int[] arr, int root, int limit) {
        int lson = 2 * root + 1;
        int rson = 2 * root + 2;
        int temp;
        if (lson <= limit && rson <= limit) {
            temp = arr[lson] > arr[rson] ? lson : rson;
        } else if (lson <= limit) {
            temp = lson;
        } else if (rson <= limit) {
            temp = rson;
        } else return;

        if (arr[temp] > arr[root]) {
            swap(arr, temp, root);
            heapfy(arr, temp, limit);
        }
    }

46 
    public static void swap(int[] arr, int i, int j) {
        int temp = arr[i];
        arr[i] = arr[j];
        arr[j] = temp;
    }
}