冒泡排序和选择排序(bubble sort and selection sort)

Bubble sort

Basic Method:

import random
nums = [random.randint(1,20) for _ in range(10)] #制作一个无序数字列表
print(nums)

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

print(nums)

Method Optimization:

import random
nums = [random.randint(1,20) for _ in range(10)] #制作一个无序数字列表
print(nums)

length = len(nums)
flag = True
for i in range(length - 1):
    flag = False
    for j in range(length - 1 - i):
        if nums[j] > nums[j + 1]:
            nums[j], nums[j + 1] = nums[j + 1], nums[j]
            flag = True
    if not flag:
        break

print(nums)

Selection sort

Basic Method

import random

nums = [random.randint(1, 20) for _ in range(10)] #制作一个无序数字列表
print(nums)

length = len(nums)
for i in range(length - 1):
    minindex = i
    for j in range(i+1, length):
        if nums[j] < nums[minindex]:
            minindex = j
    else:
        if minindex != i:
            nums[i], nums[minindex] = nums[minindex], nums[i]

print(nums)

Method Optimization 1

import random

nums = [random.randint(1, 20) for _ in range(10)] #制作一个无序数字列表
print(nums)

length = len(nums)
for i in range(length // 2):
    minindex = i
    maxindex = ~i
    for j in range(i+1, length-i):
        if nums[j] < nums[minindex]:
            minindex = j
        if nums[~j] > nums[maxindex]:
            maxindex = ~j
    if nums[maxindex] == nums[minindex]:
        break
    if minindex != i:
        nums[i], nums[minindex] = nums[minindex], nums[i]
        if maxindex == i - length:
            maxindex = minindex - length
    if maxindex != ~i:
        nums[maxindex], nums[~i] = nums[~i], nums[maxindex]

print(nums)

Method Optimization 2

import random

nums = [random.randint(1, 20) for _ in range(10)] #制作一个无序数字列表
print(nums)

length = len(nums)
for i in range(length // 2):
    minindex = i
    maxindex = i
    for j in range(i+1, length-i):
        if nums[j] < nums[minindex]:
            minindex = j
        elif nums[j] > nums[maxindex]:
            maxindex = j
    if nums[maxindex] == nums[minindex]:
        break
    if minindex != i:
        nums[i], nums[minindex] = nums[minindex], nums[i]
        if maxindex == i:
            maxindex = minindex
    if maxindex != ~i:
        nums[maxindex], nums[~i] = nums[~i], nums[maxindex]

print(nums)