1 public class test
2 {
3 public static void main(String[] args)
4 {
5 int[] array = new int[] {3,5,6,11,20,8,9,2,7};
6 createMinimumHeap(array);
7 for(int value : array)
8 System.out.print(value + " ");
9 System.out.println();
10 for(int i = 0; i < array.length; i++)
11 System.out.print(extract_Min(array, array.length - i) + " ");
12 }
13
14 //1 建堆
15 public static void createMinimumHeap(int[] array)
16 {
17 int k = array.length / 2 - 1;
18 while(k >= 0)
19 {
20 Min_Heapify(array, k, array.length);
21 k -= 1;
22 }
23 }
24
25 //2 最小堆化
26 public static void Min_Heapify(int[] array, int k, int size)
27 {
28 int min_index;
29 while(k <= size / 2 - 1)
30 {
31 if(k * 2 + 2 >= size)
32 min_index = k * 2 + 1;
33 else
34 min_index = array[k * 2 + 1] < array[k * 2 + 2] ? k * 2 + 1 : k * 2 + 2;
35 if(array[k] > array[min_index])
36 {
37 swap(array, k, min_index);
38 k = min_index;
39 }
40 else
41 break;
42 }
43 }
44
45 //3 提取最小元素
46 public static int extract_Min(int[] array, int size)
47 {
48 int key = array[0];
49 array[0] = array[size - 1];
50 //最小堆化
51 Min_Heapify(array, 0, size - 1);
52 return key;
53 }
54
55 //4 插入元素
56 //将插入的元素放在数组最后 依次与其父亲结点进行比较 直到根结点
57
58 public static void swap(int[] a, int i, int j)
59 {
60 int tmp = a[i];
61 a[i] = a[j];
62 a[j] = tmp;
63 }
64 }
