Java数据结构《排序算法》归并排序

package sort;

import java.util.Arrays;

public class MergeSort {
    public static void main(String[] args) {
        int[] arr = {6,4,8,1,5};
        int[] temp = new int[5];
        mergeSort(arr,0,4,temp);
        System.out.println(Arrays.toString(arr));
    }
    public static void mergeSort(int[] arr, int left,  int right, int[] temp){
        if (left < right){//只要不是剩一个元素就不停的拆分数组
            int mid = (left + right)/2;
            mergeSort(arr, left, mid, temp);
            mergeSort(arr, mid+1, right, temp);
            merge(arr,left,mid,right,temp);
        }
    }
    //将arr[] 中的 left到mid mid+1到right 这两个数组排序后放入arr left到right
    public static void merge(int[] arr, int left, int mid, int right, int[] temp) {
        int i = left;
        int j = mid + 1;
        int t = 0;
        //从小到大放进temp里，直到一个数组放完
        while (i<=mid && j<=right){
            if (arr[i]<arr[j]){
                temp[t] = arr[i];
                t++;
                i++;
            }else {
                temp[t] = arr[j];
                t++;
                j++;
            }
        }
        //将剩余的一个数组也放到temp里
        while (i<=mid){
            temp[t] = arr[i];
            i++;
            t++;
        }
        while (j<=right){
            temp[t] = arr[j];
            j++;
            t++;
        }
        t = 0;
        int templeft = left;
        while (templeft<=right){
            arr[templeft] = temp[t];
            t++;
            templeft++;
        }
    }
}