2
3 @Override
4 public int[] sort(int[] sourceArray) throws Exception {
5 // 对 arr 进行拷贝，不改变参数内容
6 int[] arr = Arrays.copyOf(sourceArray, sourceArray.length);
7
8 if (arr.length < 2) {
9 return arr;
10 }
11 int middle = (int) Math.floor(arr.length / 2);
12
13 int[] left = Arrays.copyOfRange(arr, 0, middle);
14 int[] right = Arrays.copyOfRange(arr, middle, arr.length);
15
16 return merge(sort(left), sort(right));
17 }
18
19 protected int[] merge(int[] left, int[] right) {
20 int[] result = new int[left.length + right.length];
21 int i = 0;
22 while (left.length > 0 && right.length > 0) {
23 if (left[0] <= right[0]) {
24 result[i++] = left[0];
25 left = Arrays.copyOfRange(left, 1, left.length);
26 } else {
27 result[i++] = right[0];
28 right = Arrays.copyOfRange(right, 1, right.length);
29 }
30 }
31
32 while (left.length > 0) {
33 result[i++] = left[0];
34 left = Arrays.copyOfRange(left, 1, left.length);
35 }
36
37 while (right.length > 0) {
38 result[i++] = right[0];
39 right = Arrays.copyOfRange(right, 1, right.length);
40 }
41
42 return result;
43 }
44
45}
6. 快速排序 6.1 算法步骤
从数列中挑出一个元素，称为 “基准”（pivot）;