快速排序

时间复杂度O(nlogn)
空间复杂度O(nlogn)

import java.util.Arrays;
public static void quickSort(int[] arr,int left, int right) {
        if(left>right){
            return;
        }
        int base = arr[left];
        int i = left; //左下标
        int j = right; //右下标
        while(i != j) {
            while( arr[j] >= base && i < j) {
                j--;
            }
            while(arr[i] <= base && i < j) {
                i++;
            }
            if(i < j){
                int temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
        arr[left] = arr[i];
        arr[i] = base;
        quickSort(arr, left, i-1);
        quickSort(arr, i+1, right);
    }

    public static void main(String[] args){
        int[] a = { 49, 38, 65, 97, 76, 13, 27, 50 };
        quickSort(a, 0, a.length-1);
        System.out.println("排好序的数组：");
        for (int e : a)
            System.out.print(e+" ");
    }
}