1 public class guiBing2 {
2 public static void mergeSort(int[] list,int[] tempList,int head,int rear){
3 if(head < rear){
4 //取分割位置
5 int middle = (head + rear) / 2;
6 //递归划分列表的左序列
7 mergeSort(list,tempList,head,middle);
8 //递归划分列表的右序列
9 mergeSort(list,tempList,middle + 1,rear);
10 //列表合并
11 merge(list,tempList,head,middle + 1,rear);
12 }
13 }
14 /**
15 * merge
16 * 合并俩表
17 */
18 public static void merge(int[] list,int[] tempList,int head,int middle,int rear){
19 //左指针尾
20 int headEnd = middle - 1;
21 //右指针头
22 int rearStart = middle;
23 //临时列表的下标
24 int tempIndex = head;
25 //列表合并后的长度
26 int tempLength = rear - head + 1;
27
28 //先循环俩个区间段都没有结束的情况
29 while ((headEnd >= head) && (rearStart <= rear)){
30 //如果发现右序列大，则将此树放入临时列表
31 if(list[head] < list[rearStart]){
32 tempList[tempIndex++] = list[head++];
33 } else {
34 tempList[tempIndex++] = list[rearStart++];
35 }
36 }
37
38 //判断左序列是否结束
39 while (head <= headEnd){
40 tempList[tempIndex++] = list[head++];
41 }
42 //判断右序列是否结束
43 while (rearStart <= rear){
44 tempList[tempIndex++] = list[rearStart++];
45 }
46
47 //交换数据
48 for (int i = 0; i < tempLength; i++) {
49 list[rear] = tempList[rear];
50 rear--;
51 }
52 }
53 }
