九大常用排序算法 python

1.冒泡排序

import random
from timewrap import *
@cal_time
def bubble_sort(li):
    for i in range(len(li)-1):

        for j in range(len(li)-i-1):
            if li[j] > li[j+1]:
                li[j],li[j+1]=li[j+1],li[j]


@cal_time
def bubble_sort_2(li):
    '''改良版'''
    for i in range(len(li)-1):
        flag = False
        for j in range(len(li)-i-1):
            if li[j] > li[j+1]:
                li[j],li[j+1]=li[j+1],li[j]
                flag=True
        if not flag:
            return

li = list(range(10000))
random.shuffle(li)
# print(li)
# bubble_sort(li)#12.725000143051147
bubble_sort_2(li)#12.974000215530396
print(li)

2.选择排序

import random

from timewrap import *

@cal_time
def select_sort(li):
    '''选择数值最小的数放在前面'''
    for i in range(len(li)-1):
        min_index = i
        for j in range(i+1,len(li)):
            if li[j] < li[min_index]:
                min_index = j
        li[i],li[min_index] = li[min_index],li[i]


li = list(range(10000))
random.shuffle(li)
print(li)
select_sort(li)
print(li)

3.插入排序

import random

from timewrap import *


@cal_time
def insert_sort(li):
    for i in range(1,len(li)):
        tmp = li[i]
        j = i-1
        while li[j] > tmp and j >= 0:
            li[j+1] = li[j]
            j-=1
        li[j+1] = tmp

li = list(range(10000))
random.shuffle(li)
print(li)
insert_sort(li)
print(li)

4.快速排序

import random
import sys

from 排序算法.timewrap import *

sys.setrecursionlimit(100000)

def partition(li, left, right):
    # ri = random.randint(left, right)
    # li[left], li[ri] = li[ri], li[left]
    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


def _quick_sort(li, left, right):
    if left < right:    # 至少有两个元素
        mid = partition(li, left, right)
        _quick_sort(li, left, mid-1)
        _quick_sort(li, mid+1, right)

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

@cal_time
def sys_sort(li):
    li.sort()

li = list(range(10000))
random.shuffle(li)


#sys_sort(li1)
quick_sort(li)

5.堆排序

import random

from 排序算法.timewrap import *


def _sift(li, low, high):
    """
    :param li:
    :param low: 堆根节点的位置
    :param high: 堆最有一个节点的位置
    :return:
    """
    i = low  # 父亲的位置
    j = 2 * i + 1  # 孩子的位置
    tmp = li[low]  # 原省长
    while j <= high:
        if j + 1 <= high and li[j + 1] > li[j]:  # 如果右孩子存在并且右孩子更大
            j += 1
        if tmp < li[j]:  # 如果原省长比孩子小
            li[i] = li[j]  # 把孩子向上移动一层
            i = j
            j = 2 * i + 1
        else:
            li[i] = tmp  # 省长放到对应的位置上(干部)
            break
    else:
        li[i] = tmp  # 省长放到对应的位置上(村民/叶子节点)


def sift(li, low, high):
    """
    :param li:
    :param low: 堆根节点的位置
    :param high: 堆最有一个节点的位置
    :return:
    """
    i = low         # 父亲的位置
    j = 2 * i + 1   # 孩子的位置
    tmp = li[low]   # 原省长
    while j <= high:
        if j + 1 <= high and li[j+1] > li[j]: # 如果右孩子存在并且右孩子更大
            j += 1
        if tmp < li[j]: # 如果原省长比孩子小
            li[i] = li[j]  # 把孩子向上移动一层
            i = j
            j = 2 * i + 1
        else:
            break
    li[i] = tmp


@cal_time
def heap_sort(li):
    n = len(li)
    # 1. 建堆
    for i in range(n//2-1, -1, -1):
        sift(li, i, n-1)
    # 2. 挨个出数
    for j in range(n-1, -1, -1):    # j表示堆最后一个元素的位置
        li[0], li[j] = li[j], li[0]
        # 堆的大小少了一个元素 （j-1）
        sift(li, 0, j-1)


li = list(range(10000))
random.shuffle(li)
heap_sort(li)
print(li)

# li=[2,9,7,8,5,0,1,6,4,3]
# sift(li, 0, len(li)-1)
# print(li)

6.并归排序

import random


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[i])
            i += 1
        else:
            ltmp.append(li[j])
            j += 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:  # 至少两个元素
        mid = (low + high) // 2
        _merge_sort(li, low, mid)
        _merge_sort(li, mid+1, high)
        merge(li, low, mid, high)
        print(li[low:high+1])


def merge_sort(li):
    return _merge_sort(li, 0, len(li)-1)


li = list(range(16))
random.shuffle(li)
print(li)
merge_sort(li)

print(li)

7.希尔排序

def insert_sort(li):
    for i in range(1, len(li)):
        # i 表示无序区第一个数
        tmp = li[i] # 摸到的牌
        j = i - 1 # j 指向有序区最后位置
        while li[j] > tmp and j >= 0:
            #循环终止条件： 1. li[j] <= tmp; 2. j == -1
            li[j+1] = li[j]
            j -= 1
        li[j+1] = tmp

def shell_sort(li):
    d = len(li) // 2
    while d > 0:
        for i in range(d, len(li)):
            tmp = li[i]
            j = i - d
            while li[j] > tmp and j >= 0:
                li[j+d] = li[j]
                j -= d
            li[j+d] = tmp
        d = d >> 1

8.内置堆模块排序

import heapq, random

li = [5,8,7,6,1,4,9,3,2]

heapq.heapify(li)
print(heapq.heappop(li))
print(heapq.heappop(li))

def heap_sort(li):
    heapq.heapify(li)
    n = len(li)
    new_li = []
    for i in range(n):
        new_li.append(heapq.heappop(li))
    return new_li

li = list(range(10000))
random.shuffle(li)
# li = heap_sort(li)
# print(li)

print(heapq.nlargest(100, li))

9.计数排序

# 0 0 1 1 2 4 3 3 1 4 5 5
import random
import copy
from timewrap import *

@cal_time
def count_sort(li, max_num = 100):
    count = [0 for i in range(max_num+1)]
    for num in li:
        count[num]+=1
    li.clear()
    for i, val in enumerate(count):
        for _ in range(val):
            li.append(i)

@cal_time
def sys_sort(li):
    li.sort()

li = [random.randint(0,100) for i in range(100000)]
li1 = copy.deepcopy(li)
count_sort(li)
sys_sort(li1)
print(li)