经典笔试题-JAVA实现快速排序算法

public class QuickSort {

    public static int partition(int a[],int p,int r){
        int x = a[r-1];
        int i = p - 1;
        int temp;
        for(int j=p;j<=r-1;j++){
            if(a[j-1]<=x){
                i++;
                temp = a[j-1];
                a[j-1] = a[i-1];
                a[i-1] = temp;
            }
        }
        temp = a[r-1];
        a[r-1] = a[i];
        a[i] = temp;
        return i+1;
    }

    public static void quickSort(int a[],int p,int r){
        if(p < r){
            int q = partition(a, p, r);
            quickSort(a, p, q-1);
            quickSort(a, q+1, r);
        }
    }

    public static void main(String[] args) {
        int a[] = {23,56,77,45,15,476,784,24,54,78};
        quickSort(a,1,10);
        for (int i : a) {
            System.out.println(i);
        }
    }
}