sort
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NIngCoder
parent
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@ -1,37 +1,47 @@
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'''
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File: bubble_sort.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Author: timi (xisunyy@163.com)
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'''
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import sys, os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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import sys
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import os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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"冒泡排序"
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"""冒泡排序"""
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def bubble_sort(nums):
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n = len(nums)
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# 外循环：待排序元素数量为 n-1, n-2, ..., 1
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for i in range(n-1, -1, -1):
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# 内循环：冒泡操作
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for j in range(i):
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# 交换 nums[j] 与 nums[j + 1]
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if nums[j] > nums[j+1]:
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nums[j], nums[j+1] = nums[j+1], nums[j]
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"冒泡排序（标志优化）"
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def bubbleSortWithFlag(nums):
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"""冒泡排序（标志优化）"""
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def bubble_sort_with_flag(nums):
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n = len(nums)
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# 外循环：待排序元素数量为 n-1, n-2, ..., 1
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for i in range(n-1, -1, -1):
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flag = False # 初始化标志位
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# 内循环：冒泡操作
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for j in range(i):
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# 交换 nums[j] 与 nums[j + 1]
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if nums[j] > nums[j+1]:
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nums[j], nums[j+1] = nums[j+1], nums[j]
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flag = True # 记录交换元素
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if not flag:break
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if not flag:
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break # 此轮冒泡未交换任何元素，直接跳出
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if __name__ == '__main__':
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nums = [4, 1, 3, 1, 5, 2]
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bubble_sort(nums)
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print("冒泡排序后数组 nums = " ,nums)
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bubbleSortWithFlag(nums)
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print("冒泡排序后数组 nums = " ,nums)
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print("排序后数组 nums = ", nums)
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nums1 = [4, 1, 3, 1, 5, 2]
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bubble_sort_with_flag(nums1)
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print("排序后数组 nums = ", nums1)
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@ -1,15 +1,16 @@
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'''
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File: insertion_sort.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Author: timi (xisunyy@163.com)
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'''
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import sys, os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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import sys
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import os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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"直接插入排序"
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def insertionSort(nums):
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"""插入排序"""
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def insertion_sort(nums):
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# 外循环：base = nums[1], nums[2], ..., nums[n-1]
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for i in range(1, len(nums)):
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base = nums[i]
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@ -20,7 +21,8 @@ def insertionSort(nums):
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j -= 1
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nums[j+1] = base # 2. 将 base 赋值到正确位置
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if __name__ == '__main__':
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nums = [4, 1, 3, 1, 5, 2]
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insertionSort(nums)
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insertion_sort(nums)
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print("排序后数组 nums = ", nums)
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@ -1,48 +1,60 @@
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'''
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File: merge_sort.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Author: timi (xisunyy@163.com)
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'''
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import sys, os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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import copy
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from include import *
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import sys
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import os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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"""
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另一种 思路实现归并排序
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合并左子数组和右子数组
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左子数组区间 [left, mid]
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右子数组区间 [mid + 1, right]
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"""
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def merge_sort(nums,l,r):
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if l>=r:return
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mid=l+r>>1 #划分中点
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#进行归并
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merge_sort(nums,l,mid)
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merge_sort(nums,mid+1,r)
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k,i,j=0,l,mid+1 #借助辅助数组 完成排序
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while i<=mid and j<=r:
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if nums[i]<=nums[j]: #这一步保证了 稳定排序
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help_ls[k]=nums[i]
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i+=1
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else:
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help_ls[k]=nums[j]
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def merge(nums, left, mid, right):
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# 初始化辅助数组 借助 copy模块
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tmp = copy.deepcopy(nums[left:right+1])
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# 左子数组的起始索引和结束索引
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leftStart, leftEnd = left-left, mid - left
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# 右子数组的起始索引和结束索引
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rightStart, rightEnd = mid + 1 - left, right - left
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# i, j 分别指向左子数组、右子数组的首元素
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i, j = leftStart, rightStart
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# 通过覆盖原数组 nums 来合并左子数组和右子数组
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for k in range(left, right+1):
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# 若 “左子数组已全部合并完”，则选取右子数组元素，并且 j++
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if i > leftEnd:
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nums[k] = tmp[j]
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j += 1
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# 否则，若 “右子数组已全部合并完” 或 “左子数组元素 < 右子数组元素”，则选取左子数组元素，并且 i++
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elif j > rightEnd or tmp[i] <= tmp[j]:
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nums[k] = tmp[i]
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i += 1
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# 否则，若 “左子数组元素 > 右子数组元素”，则选取右子数组元素，并且 j++
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else:
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nums[k] = tmp[j]
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j += 1
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k+=1
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while i<=mid: #对于左边区域
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help_ls[k]=nums[i]
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k,i=k+1,i+1
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while j<=r: #对于右边区域
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help_ls[k]=nums[j]
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k,j=k+1,j+1
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i,j=l,0
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while i<=r:
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nums[i]=help_ls[j]
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i,j=i+1,j+1
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"""归并排序"""
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def merge_sort(nums, left, right):
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# 终止条件
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if left >= right:
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return # 当子数组长度为 1 时终止递归
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# 划分阶段
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mid = left + right >> 1 # 计算中点
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merge_sort(nums, left, mid) # 递归左子数组
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merge_sort(nums, mid + 1, right) # 递归右子数组
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# 合并阶段
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merge(nums, left, mid, right)
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if __name__ == '__main__':
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nums = [4, 1, 3, 1, 5, 2]
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n=len(nums)
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help_ls=[0 for _ in range(n)]
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merge_sort(nums,0,n-1)
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merge_sort(nums, 0, len(nums)-1)
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print("归并排序完成后 nums = ", nums)
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@ -1,31 +1,132 @@
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'''
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File: quick_sort.py
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Created Time: 2022-11-25
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Author: Krahets (krahets@163.com)
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Author: timi (xisunyy@163.com)
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'''
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import sys, os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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from include import *
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import sys
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import os.path as osp
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sys.path.append(osp.dirname(osp.dirname(osp.abspath(__file__))))
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"另一种思维 实现快速排序"
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def quick_sort(nums,l,r):
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if l>=r:
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return
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i,j,x=l-1,r+1,nums[l+r>>1]
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"""快速排序类"""
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class quick_sort(object):
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"""哨兵划分"""
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def partition(self, nums, left, right):
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# 以 nums[left] 作为基准数
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i, j = left, right
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while i < j:
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while True:
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i+=1
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if nums[i]>=x:break
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while True:
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j-=1
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if nums[j]<=x:break
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if i<j:nums[i],nums[j]=nums[j],nums[i]
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quick_sort(nums,l,j),quick_sort(nums,j+1,r)
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while i < j and nums[j] >= nums[left]:
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j -= 1 # 从右向左找首个小于基准数的元素
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while i < j and nums[i] <= nums[left]:
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i += 1 # 从左向右找首个大于基准数的元素
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# 元素交换
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nums[i], nums[j] = nums[j], nums[i]
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# 将基准数交换至两子数组的分界线
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nums[i], nums[left] = nums[left], nums[i]
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return i # 返回基准数的索引
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"""快速排序"""
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def quick_sort(self, nums, left, right):
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# 子数组长度为 1 时终止递归
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if left >= right:
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return
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# 哨兵划分
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pivot = self.partition(nums, left, right)
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# 递归左子数组、右子数组
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self.quick_sort(nums, left, pivot-1)
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self.quick_sort(nums, pivot+1, right)
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"""快速排序类（中位基准数优化）"""
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class quick_sort_median():
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# 选取三个元素的中位数
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def median_three(self, nums, left, mid, right):
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# 使用了异或操作来简化代码
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# 异或规则为 0 ^ 0 = 1 ^ 1 = 0, 0 ^ 1 = 1 ^ 0 = 1
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if (nums[left] > nums[mid]) ^ (nums[left] > nums[right]):
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return left
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elif (nums[mid] < nums[left]) ^ (nums[mid] > nums[right]):
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return mid
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return right
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"""哨兵划分（三数取中值）"""
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def partition(self, nums, left, right):
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# 以 nums[left] 作为基准数
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med = self.median_three(nums, left, (left+right)//2, right)
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# 将中位数交换至数组最左端
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nums[left], nums[med] = nums[med], nums[left]
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# 以 nums[left] 作为基准数
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i, j = left, right
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while i < j:
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while i < j and nums[j] >= nums[left]:
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j -= 1 # 从右向左找首个小于基准数的元素
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while i < j and nums[i] <= nums[left]:
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i += 1 # 从左向右找首个大于基准数的元素
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# 元素交换
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nums[i], nums[j] = nums[j], nums[i]
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# 将基准数交换至两子数组的分界线
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nums[i], nums[left] = nums[left], nums[i]
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return i # 返回基准数的索引
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"""快速排序"""
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def quick_sort(self, nums, left, right):
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# 子数组长度为 1 时终止递归
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if left >= right:return
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# 哨兵划分
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pivot = self.partition(nums, left, right)
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# 递归左子数组、右子数组
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self.quick_sort(nums, left, pivot-1)
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self.quick_sort(nums, pivot+1, right)
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"""快速排序类（尾递归优化）"""
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class quick_sort_tail_call():
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"""哨兵划分"""
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def partition(self, nums, left, right):
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# 以 nums[left] 作为基准数
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i, j = left, right
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while i < j:
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while i < j and nums[j] >= nums[left]:
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j -= 1 # 从右向左找首个小于基准数的元素
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while i < j and nums[i] <= nums[left]:
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i += 1 # 从左向右找首个大于基准数的元素
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# 元素交换
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nums[i], nums[j] = nums[j], nums[i]
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# 将基准数交换至两子数组的分界线
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nums[i], nums[left] = nums[left], nums[i]
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return i # 返回基准数的索引
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"""快速排序（尾递归优化）"""
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def quick_sort(self, nums, left, right):
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# 子数组长度为 1 时终止
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while left < right:
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# 哨兵划分操作
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pivot = self.partition(nums, left, right)
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# 对两个子数组中较短的那个执行快排
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if pivot-left < right-pivot:
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self.quick_sort(nums, left, pivot-1) # 递归排序左子数组
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left = pivot+1 # 剩余待排序区间为 [pivot + 1, right]
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else:
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self.quick_sort(nums, pivot+1, right) # 递归排序右子数组
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right = pivot-1 # 剩余待排序区间为 [left, pivot - 1]
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if __name__ == '__main__':
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# 快速排序
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nums = [4, 1, 3, 1, 5, 2]
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n=len(nums)
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help_ls=[0 for _ in range(n)]
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quick_sort(nums,0,n-1)
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quick_sort().quick_sort(nums, 0, len(nums)-1)
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print("快速排序完成后 nums = ", nums)
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# 快速排序（中位基准数优化）
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nums1 = [4, 1, 3, 1, 5, 2]
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quick_sort_median().quick_sort(nums1, 0, len(nums1)-1)
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print("快速排序（中位基准数优化）完成后 nums = ", nums)
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# 快速排序（尾递归优化）
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nums2 = [4, 1, 3, 1, 5, 2]
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quick_sort_tail_call().quick_sort(nums, 0, len(nums2)-1)
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print("快速排序（尾递归优化）完成后 nums = ", nums)
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