快速排序的递归非递归实习java

package com.edu.hpu.sort.swap.quick;

import java.util.Arrays;
import java.util.LinkedList;

import com.edu.hpu.sort.Sort;

public class QuickSort extends Sort {

@Override
public int[] doSort(int[] arr) {
return quickSort2(arr, 0, arr.length - 1);
}

@SuppressWarnings("unused")
private int [] quickSort(int [] arr, int p, int r){
// 递归求解
if(p < r){
int q = partition(arr, p, r);
quickSort(arr, p, q - 1);
quickSort(arr, q + 1, r);
}
return arr;
}
private int [] quickSort2(int [] arr, int p, int r){
// 非递归求解
if(p < r){
LinkedList<Integer> stack = new LinkedList<Integer>();
int q = partition(arr, p, r);
if(p < q - 1){
stack.push(q - 1);
stack.push(p);
}
if(r > q + 1){
stack.push(r);
stack.push(q + 1);
}
while(!stack.isEmpty()){
int l = stack.pop();
int h = stack.pop();
int mid = partition(arr, l, h);
if(l < mid - 1){
stack.push(mid - 1);
stack.push(l);
}
if(h > mid + 1){
stack.push(h);
stack.push(mid + 1);
}
}
}
return arr;
}

private int partition(int []arr, int p, int r){
int aix = arr[r];
int i = p -1;
for(int j = p; j < r; j++){
if(arr[j] < aix){
i++;
swap(arr, i, j);
}
}
swap(arr, i + 1, r);
System.out.println(Arrays.toString(arr));
return i + 1;
}
public static void main(String[] args) {
QuickSort quickSort = new QuickSort();
quickSort.printOrder(new int []{4, 1, 3, 2, 16, 9, 100, 194, 8, 7});
}
}