快速排序征服方法？

编程入门行业动态更新时间:2024-10-11 13:28:24

本文介绍了快速排序征服方法？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

我认为合并排序是划分和征服，因为

/ strong> - 数组字面上划分为不需要任何处理的子数组（比较/交换），问题大小减半/已分配/ ....

Conquer - merge（）处理的这些子数组（/比较/交换）

代码给人的印象是它是Divide& Conquer，

if（hi < = lo）return; int mid = lo +（hi-lo）/ 2; //否（比较/交换）元素之前分配 sort（a，aux，lo，mid）; //问题减半（Divide） sort（a，aux，mid + 1，hi）; merge（a，aux，lo，mid）; //（比较/交换）发生在合并 - 征服

合并排序跟踪说，该问题被粒化，然后处理，

但是在快速排序中，

首先， strong>处理（比较/交换）使用分区元素（枢轴）并修复枢轴的最终位置，然后问题大小减半/已分配/分区，

代码没有给人分歧的印象征服，

if（hi< = lo）return; int j = partition（a，lo，hi）;你叫这个分割阶段吗？ sort（a，lo，j-1）; //这看起来像分割阶段，因为问题减半 sort（a，j + 1，hi）;

快速排序跟踪，显示处理已开始在完整的数组上，然后达到粒度级，

问题：

我对 Divide 阶段的理解意味着减少（一半）问题大小。在快速排序中，您是否以分割阶段来考虑处理（比较/交换）数组和分区？

我对征服阶段的理解意味着收集/合并。快速排序，征服阶段是什么意思？

注意：初学者，排序算法

解决方案

Divide&征服算法有三个阶段：

分割

征服

合并，

对于合并排序（ www.cs.umd.edu/~meesh/351/mount/lectures/lect6-divide -conquer-mergesort.pdf ）：

分割：将数组拆分成2个子阵列，

征服：合并对结果子数组进行递归排序，

合并：将两个排序的子数据合并到一个排序的列表中。

要快速排序（ www.cs.rochester.edu/~gildea/csc282/slides/C07-quicksort.pdf ）：

分隔：首先重新排列，然后将阵列分成2个子阵列，

征服：递归地快速排序生成的子数组，

Com bine：无。

注意：感谢罗切斯特大学和马里兰大学CS部门。 p>

I consider Merge sort as divide and conquer because,

Divide - Array is literally divided into sub arrays without any processing(compare/swap), and the problem sized is halved/Quartered/....

Conquer - merge() those sub arrays by processing(compare/swap)

Code gives an impression that it is Divide&Conquer,

if(hi <= lo) return; int mid = lo + (hi-lo)/2; //No (compare/swap) on elements before divide sort(a, aux, lo, mid); // Problem is halved(Divide) sort(a, aux, mid+1, hi); merge(a, aux, lo, mid); // (Compare/swap) happens here during Merge - Conquer

Merge sort trace says, that problem is granulated and then processed,

But in Quick sort,

Firstly, Complete array is processed(compare/swap) using a partition element(pivot) and fix the final position of pivot, and then problem size is halved/Quartered/.... for re-partitioning,

Code does not give an impression of divide & conquer,

if(hi <= lo) return; int j = partition(a, lo, hi); // Do you call this divide phase? sort(a, lo, j-1); // This looks like divide phase, because problem is halved sort(a, j+1, hi);

Quick sort trace, shows that processing is started on complete array and then reaches granular level,

Questions:

My understanding of Divide phase mean, reducing(half) the problem size. In Quick sort, do you consider processing(compare/swap) array and partition using pivot, as Divide phase?

My understanding of Conquer phase mean, gathering/merging back. In quick sort, Where does conquer phase mean?

Note: Am a beginner, in sorting algorithms

解决方案

Divide & Conquer algorithms have 3 stages:

Divide,

Conquer,

Combine,

For merge sort (www.cs.umd.edu/~meesh/351/mount/lectures/lect6-divide-conquer-mergesort.pdf):

Divide: Split the array into 2 subarrays,

Conquer: Merge sort the resulting subarrays recursively,

Combine: Merge the two sorted subarrays into a single sorted list.

For quick sort (www.cs.rochester.edu/~gildea/csc282/slides/C07-quicksort.pdf):