归并排序（java实现）

归并排序（java实现）

 1     public static void sort(int[] a,int low,int high){
 2         int mid = (low+high)/2;
 3         if(low<high){    //最小单元不为1时继续拆分
 4             sort(a,low,mid);    //拆分左边
 5             sort(a,mid+1,high);  //拆分右边
 6            //合并
 7             merge1(a, low, mid+1, high);
 8         }
 9         return;
10     }
11     public static void merge1(int[]a,int low,int mid,int high) {
12         int[]temp = new int[high-low+1];
13         
14         int i = low,j = mid,k =0;    //拆分后比较存入临时数组
15         while(i<mid&&j<=high) {
16             if(a[i]<a[j]) {
17                 temp[k++] = a[i++];
18             }else {
19                 temp[k++] = a[j++];
20             }
21         }
22         while(i<mid) {        //左边剩余的
23             temp[k++] = a[i++];
24         }
25         
26         while(j<=high) {      //右边剩余的  
27             temp[k++] = a[j++];
28         }
29         for(i =0;i<temp.length;i++) {    //替换掉
30             a[i+low] = temp[i];
31         }
32     }

测试：

1 public static void main(String[] args) {
2         int[]a = {1,3,5,8,3,12,6,9};
3         sort(a,0,7);
4         for(int i=0;i<a.length;i++) {
5             System.out.print(a[i]+" ");
6         }
7     }

结果：

 

posted @ 2018-10-12 13:45 板栗子 阅读( ...) 评论( ...) 编辑 收藏