参考资料

复习基础排序算法（Java）

快速排序

import java.util.Random;
class Solution {
    private static final Random RANDOM = new Random();
    public int[] sortArray(int[] nums) {
        quickSort(nums,0,nums.length-1);
        return nums;
    }
    public void quickSort(int[] nums,int start,int end){
        if(start >= end){
            return;
        }
        int k = partition(nums,start,end);
        quickSort(nums,start,k-1);
        quickSort(nums,k+1,end);
    }

    public int partition(int[] nums,int start,int end){
     int randomIndex = RANDOM.nextInt(end - start + 1) + start;
        swap(nums, start, randomIndex);


        int priot = nums[start];
        int index = start;// [start,index-1]<priot,[index+1,end]>=priot
        for(int i= start+1;i<=end;i++){
            if(nums[i]<priot){
                index++;
                swap(nums,i,index);
            }
        }
        swap(nums,start,index);
        return index;
    }

    public void swap(int[] nums,int i, int j){
        int tmp = nums[i];
        nums[i] = nums[j];
        nums[j] = tmp;
    }
}

插入排序

归并排序