本文主要是介绍每天刷个算法题20160525：快速排序的递归转非递归解法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
版权所有。所有权利保留。
欢迎转载，转载时请注明出处：
http://blog.csdn.net/xiaofei_it/article/details/51524798
为了防止思维僵化，每天刷个算法题。已经刷了几天了，现在发点代码。
我已经建了一个开源项目，每天的题目都在里面：
https://github.com/Xiaofei-it/Algorithms
绝大部分算法都是我自己写的，没有参考网上通用代码。读者可能会觉得有的代码晦涩难懂，因为那是我自己的理解。
最近几天都是在写一些原来的东西，大多数是非递归。以后准备刷点DP、贪心之类的题。
下面是快速排序的递归转非递归解法。
是不是没有人像我这样蛋疼地把快速排序写成非递归的？？？
/**** Copyright 2016 Xiaofei** Licensed under the Apache License, Version 2.0 (the "License");* you may not use this file except in compliance with the License.* You may obtain a copy of the License at** http://www.apache.org/licenses/LICENSE-2.0** Unless required by applicable law or agreed to in writing, software* distributed under the License is distributed on an "AS IS" BASIS,* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.* See the License for the specific language governing permissions and* limitations under the License.**/package xiaofei.algorithm;import java.util.Stack;/*** Created by Xiaofei on 16/5/25.**/
public class QuickSort {private static int[] array;private static void sortCorecursively(int l, int r) {class Element {int l;int r;int i;int state;//这里用state表示通用状态，和之前非递归代码风格不一样。Element(int l, int r) {this.l = l;this.r = r;this.i = -1;this.state = 0;}}Stack<Element> stack = new Stack<>();stack.push(new Element(l, r));while (!stack.isEmpty()) {Element element = stack.peek();if (element.state == 0) {int i = element.l, j = element.r, m = array[(i + j) / 2];do {while (array[i] < m) {++i;}while (m < array[j]) {--j;}if (i <= j) {int temp = array[i];array[i] = array[j];array[j] = temp;++i;--j;}} while (i <= j);element.i = i;if (element.l < j) {stack.push(new Element(element.l, j));}element.state = 1;} else if (element.state == 1) {if (element.i < element.r) {stack.push(new Element(element.i, element.r));}element.state = 2;} else if (element.state == 2) {stack.pop();}}}public static void sort(int[] array) {QuickSort.array = array;sortCorecursively(0, array.length - 1);}}
这篇关于每天刷个算法题20160525：快速排序的递归转非递归解法的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
