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 }