列表排序之NB三人组附加一个希尔排序

NB三人组之 快速排序

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  # 当left和right都指向同一个角标时
    return left


def _quick_sort(li, left, right):
    if left < right:
        mid = partition(li, left, right)
        _quick_sort(li, left, mid-1)
        _quick_sort(li, mid+1, right)

def quick_sort(li):
    _quick_sort(li, 0, len(li)-1)

NB三人组之 堆排序

def sift(li, low, high):
    i = low
    j = 2*i + 1
    tmp = li[low]
    while j <= high:
        if j + 1 <= high and li[j] < li[j+1]:
        # j<=high表示如果有两个分支  如果左边孩子小于右边孩子那么交换
            j = j+1
        if tmp < li[j]:
            li[i] = li[j]
            i = j
            j = i*2 + 1
        else:
            break
    li[i] = tmp


def heap_sort(li):
    n = len(li)
    for i in range(n//2-1, -1, -1):
        sift(li, i, n-1)
     # 开始出数
    for i in range(n-1, -1, -1):
        li[i], li[0] = li[0], li[i]
        # 现在堆的范围是0 ~ i-1 i的位置用来存放出数的值
        sift(li, 0, i-1)

NB三人组之 归并排序

 

def merge(li, low, mid, high):
    i = low
    j = mid + 1
    ltmp = []
    while i <= mid and j <= high:
        if li[i] > li[j]:
            ltmp.append(li[j])
            j += 1
        else:
            ltmp.append(li[i])
            i += 1
    while i <= mid:
        ltmp.append(li[i])
        i += 1
    while j <= high:
        ltmp.append(li[j])
        j += 1
    li[low:high+1] = ltmp


def merge_sort(li, low, high):
    if low < high:
        mid = (low + high) // 2
        merge_sort(li, low, mid)
        merge_sort(li, mid+1, high)
        merge(li, low, mid, high)

 附加之 希尔排序（插入排序的变种）

def insert_sort_gap(li, gap):
    for i in range(1, len(li)): # i是摸到的牌的下标
        tmp = li[i]
        j = i - gap # j是手里最后一张牌的下标
        while j >= 0 and li[j] > tmp:   # 两个终止条件：j小于0表示tmp是最小的 顺序不要乱
            li[j+gap] = li[j]
            j -= gap
        li[j+gap] = tmp

@cal_time
def shell_sort(li):
    d = len(li) // 2
    while d > 0:
        insert_sort_gap(li, d)
        d = d // 2