快速排序使用分治法（Divide and conquer）策略來把一個序列（list）分為兩個子序列（sub-lists）。

快速排序又是一種分而治之思想在排序演算法上的典型應用。本質上來看，快速排序應該算是在氣泡排序基礎上的遞迴分治法。

public class Test {

    public static void main(String[] args) {
        int[] arr = {49, 38, 65, 97, 23, 76, 1};
        quickSort(arr, 0, arr.length - 1);
        System.out.println(
 
"排序後:");
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
    }

    public static void quickSort(int[] arr, int low, int high) {
        if (low >= high) {
            return;
        }
        int index = getIndex(arr, low, high);
        quickSort(arr, low, index 
 
- 1);
        quickSort(arr, index + 1, high);
    }

    public static int getIndex(int[] arr, int low, int high) {
        int temp = arr[low];
        while (low < high) {
            while (low < high && arr[high] >= temp) {
                high--;
            }
            arr[low] 
 
= arr[high];
            while (low < high && arr[low] < temp) {
                low++;
            }
            arr[high] = arr[low];
        }
        arr[low] = temp;
        return low;
    }
}