基数排序-526互联

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# -*- coding: utf-8 -*-

# O(n) O(kn)
# NB O(nlogn)
import random


def partition(li, left, right):
    tmp = li[left]
    while left < right:
        while left < right and li[right] >= tmp:  # 从右面找比tmp小的数
            right -= 1  # 往左走一步
        li[left] = li[right]  # 把右边的值写到左边空位上
        # print(li, 'right')
        while left < right and li[left] <= tmp:
            left += 1
        li[right] = li[left]  # 把左边的值写到右边空位上
        # print(li, 'left')
    li[left] = tmp  # 把tmp归位
    return left


def radix_sort(li):
    max_num = max(li)  # 最大值 9->1, 99->2, 888->3, 10000->5
    it = 0
    while 10 ** it <= max_num:
        buckets = [[] for _ in range(10)]
        for var in li:
            # 987 it=1  987//10->98 98%10->8;    it=2  987//100->9 9%10=9
            digit = (var // 10 ** it) % 10
            buckets[digit].append(var)
        # 分桶完成
        li.clear()
        for buc in buckets:
            li.extend(buc)
        # 把数重新写回li
        it += 1


li = [random.randint(0, 10) for _ in range(10)]
random.shuffle(li)
print(li)

radix_sort(li)
print(li)

基数

基数方法