归并排序java

 import java.util.Arrays;

 public class MergeSort {

     public static void main(String[] args) {
         MergeSort ms=new MergeSort();
         int[] arr={5,44,32,4,566,67,23};
         ms.merge(arr, 0, arr.length-1);
         System.out.println(Arrays.toString(arr));
     }

     void merge(int[] arr,int start,int end )
     {
         if(start==end)
             return ;
         int mid=(start+end)/2;
         merge(arr,start,mid);//左边排序递归
         merge(arr,mid+1,end);//you边排序递归
         combine(arr,start,mid,end);
     }

     void combine(int[] arr,int start,int mid,int end) {
         int length=end-start+1;
         int tempArr[]=new int[length];
         int tempIndex=0;
         int left=start;
         int right=mid+1;
         while(left<=mid&&right<=end)
         {
             if(arr[left]<arr[right])
                 tempArr[tempIndex++]=arr[left++];
             else
                 tempArr[tempIndex++]=arr[right++];
         }

         while(left<=mid)
             tempArr[tempIndex++]=arr[left++];

         while(right<=end)
             tempArr[tempIndex++]=arr[right++];

         for(int i=0;i<tempArr.length;i++)
         {
             arr[start+i]=tempArr[i];
         }
     }
 }