1 package com.array;
2
3 import java.util.Arrays;
4
5 public class HeapSort {
6 public static void main(String[] args) {
7 int[] a = {45,14,5,24,5,62,7,84,34,14};
8 buildHeap(a);
9
10 System.out.println(Arrays.toString(a));
11 heapSort(a);
12 System.out.println(Arrays.toString(a));
13 }
14 public static void heapSort(int[] arr) {
15 buildHeap(arr);
16 for (int i = arr.length - 1; i >= 0; i--) {
17 swap(arr, 0, i);
18 heapfy(arr, 0, i-1);
19 }
20 }
21
22 public static void buildHeap(int[] arr) {
23 for (int i = arr.length / 2 - 1; i >= 0; i--) {
24 heapfy(arr, i, arr.length - 1);
25 }
26 }
27
28 public static void heapfy(int[] arr, int root, int limit) {
29 int lson = 2 * root + 1;
30 int rson = 2 * root + 2;
31 int temp;
32 if (lson <= limit && rson <= limit) {
33 temp = arr[lson] > arr[rson] ? lson : rson;
34 } else if (lson <= limit) {
35 temp = lson;
36 } else if (rson <= limit) {
37 temp = rson;
38 } else return;
39
40 if (arr[temp] > arr[root]) {
41 swap(arr, temp, root);
42 heapfy(arr, temp, limit);
43 }
44 }
45
46
47 public static void swap(int[] arr, int i, int j) {
48 int temp = arr[i];
49 arr[i] = arr[j];
50 arr[j] = temp;
51 }
52 }
