From 121cb10209086d385cc84a3fb992932a106a15bc Mon Sep 17 00:00:00 2001 From: NIngCoder Date: Fri, 25 Nov 2022 15:47:05 +0800 Subject: [PATCH] =?UTF-8?q?Python=E6=8E=92=E5=BA=8F=E9=83=A8=E5=88=86?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- codes/python/chapter_sorting/bubble_sort.py | 27 +++++++++++++ .../python/chapter_sorting/insertion_sort.py | 16 ++++++++ codes/python/chapter_sorting/merge_sort.py | 38 +++++++++++++++++++ codes/python/chapter_sorting/quick_sort.py | 21 ++++++++++ 4 files changed, 102 insertions(+) diff --git a/codes/python/chapter_sorting/bubble_sort.py b/codes/python/chapter_sorting/bubble_sort.py index 2027047..521dd8a 100644 --- a/codes/python/chapter_sorting/bubble_sort.py +++ b/codes/python/chapter_sorting/bubble_sort.py @@ -8,3 +8,30 @@ import sys, os.path as osp sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__)))) from include import * +"冒泡排序" +def bubble_sort(nums): + n=len(nums) + # 外循环：待排序元素数量为 n-1, n-2, ..., 1 + for i in range(n-1,-1,-1): + # 内循环：冒泡操作 + for j in range(i): + if nums[j]>nums[j+1]: + nums[j],nums[j+1]=nums[j+1],nums[j] +"冒泡排序（标志优化）" +def bubbleSortWithFlag(nums): + n=len(nums) + # 外循环：待排序元素数量为 n-1, n-2, ..., 1 + for i in range(n-1,-1,-1): + flag=False #初始化标志位 + # 内循环：冒泡操作 + for j in range(i): + if nums[j]>nums[j+1]: + nums[j],nums[j+1]=nums[j+1],nums[j] + flag=True #记录交换元素 + if not flag:break +if __name__=='__main__': + nums=[4,1,3,1,5,2] + bubble_sort(nums) + print("冒泡排序后数组 nums = " ,nums) + bubbleSortWithFlag(nums) + print("冒泡排序后数组 nums = " ,nums) \ No newline at end of file diff --git a/codes/python/chapter_sorting/insertion_sort.py b/codes/python/chapter_sorting/insertion_sort.py index 28e0331..8640abc 100644 --- a/codes/python/chapter_sorting/insertion_sort.py +++ b/codes/python/chapter_sorting/insertion_sort.py @@ -8,3 +8,19 @@ import sys, os.path as osp sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__)))) from include import * +"直接插入排序" +def insertionSort(nums): + #外循环：base = nums[1], nums[2], ..., nums[n-1] + for i in range(1,len(nums)): + base=nums[i] + j=i-1 + #内循环：将 base 插入到左边的正确位置 + while j>=0 and nums[j]>base: + nums[j+1]=nums[j] #1. 将 nums[j] 向右移动一位 + j-=1 + nums[j+1]=base #2. 将 base 赋值到正确位置 + +if __name__=='__main__': + nums=[4,1,3,1,5,2] + insertionSort(nums) + print("排序后数组 nums = " ,nums) \ No newline at end of file diff --git a/codes/python/chapter_sorting/merge_sort.py b/codes/python/chapter_sorting/merge_sort.py index 6f9b4a6..04c7130 100644 --- a/codes/python/chapter_sorting/merge_sort.py +++ b/codes/python/chapter_sorting/merge_sort.py @@ -8,3 +8,41 @@ import sys, os.path as osp sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__)))) from include import * + +""" +另一种 思路实现归并排序 +""" +def merge_sort(nums,l,r): + if l>=r:return + mid=l+r>>1 #划分中点 + #进行归并 + merge_sort(nums,l,mid) + merge_sort(nums,mid+1,r) + + k,i,j=0,l,mid+1 #借助辅助数组 完成排序 + while i<=mid and j<=r: + if nums[i]<=nums[j]: #这一步保证了 稳定排序 + help_ls[k]=nums[i] + i+=1 + else: + help_ls[k]=nums[j] + j+=1 + k+=1 + + while i<=mid: #对于左边区域 + help_ls[k]=nums[i] + k,i=k+1,i+1 + while j<=r: #对于右边区域 + help_ls[k]=nums[j] + k,j=k+1,j+1 + + i,j=l,0 + while i<=r: + nums[i]=help_ls[j] + i,j=i+1,j+1 +if __name__=='__main__': + nums=[4,1,3,1,5,2] + n=len(nums) + help_ls=[0 for _ in range(n)] + merge_sort(nums,0,n-1) + print("归并排序完成后 nums = ",nums) \ No newline at end of file diff --git a/codes/python/chapter_sorting/quick_sort.py b/codes/python/chapter_sorting/quick_sort.py index a668096..f66ff5f 100644 --- a/codes/python/chapter_sorting/quick_sort.py +++ b/codes/python/chapter_sorting/quick_sort.py @@ -8,3 +8,24 @@ import sys, os.path as osp sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__)))) from include import * + +"另一种思维 实现快速排序" +def quick_sort(nums,l,r): + if l>=r: + return + i,j,x=l-1,r+1,nums[l+r>>1] + while i=x:break + while True: + j-=1 + if nums[j]<=x:break + if i