快速排序,归并排序

快速排序

def quick_sort(li, left, right):
    if left < right:
        mid = partition(li, left, right)
        quick_sort(li, left, mid-1)     # 递归排列左部分
        quick_sort(li, mid+1, right)    # 递归排列右部分



#  将列表切割为两段
def partition(li, left, right):
    tmp = li[left]
    while left < right:
        while left < right and li[right] >= tmp:
            right -= 1
        li[left] = li[right]

        while left < right and li[left] <= tmp:
            left += 1
        li[right] = li[left]
    li[left] = tmp
    return left

import random
li = list(range(100))
random.shuffle(li)
quick_sort(li, 0, len(li)-1)
print(li)

  归并排序

def merge(li, low, mid, high):
    # 列表两段有序: [low, mid] [mid+1, high]
    i = low
    j = mid + 1
    li_tmp = []
    while i <= mid and j <= high:
        if li[i] <= li[j]:
            li_tmp.append(li[i])
            i += 1
        else:
            li_tmp.append(li[j])
            j += 1
    while i <= mid:
        li_tmp.append(li[i])
        i += 1
    while j <= high:
        li_tmp.append(li[j])
        j += 1
    # li_tmp[0:high-low+1] li[low:high+1]
    for i in range(low, high+1):
        li[i] = li_tmp[i-low]
    # li[low:high+1] = li_tmp

def _merge_sort(li, low, high): #排序li的low到high的范围
    if low < high:
        mid = (low + high) // 2
        _merge_sort(li, low, mid)
        _merge_sort(li, mid+1, high)
        # print(li[low:mid + 1], li[mid + 1:high + 1])
        merge(li, low, mid, high)
        # print(li[low: high + 1])


li = [10, 4, 6, 3, 8, 2, 5, 7]
_merge_sort(li, 0, len(li)-1)
print(li)

  

原文地址:https://www.cnblogs.com/feifeifeisir/p/10561777.html