作业·八

1. 冒泡排序、选择排序 ```python def bubble_sort(l): for i in range(len(l), 0, -1):

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

   return l

def select_sort(l): for i in range(len(l)): max_pos = l.index(max(l[i:])) l[i], l[max_pos] = l[max_pos], l[i] return l

li = [34, 32, 67, 23, 12, 7, 4, 1]

print(bubble_sort(li.copy())) print(select_sort(li.copy()))

2. 代码

2.1 九九乘法表
```python
for i in range(1, 10):
    for j in range(1, i+1):
        if i == j:
            print(f"{i} x {j} = {i*j}")
        else:
            print(f"{i} x {j} = {i*j}", end=', ')

2.2 完全数

def perfect_number_judgement(num):
    gap = int(num**0.5)

    factors = []
    for i in range(1, gap+1):
        if num % i == 0:
            factors.append(i)
            if i!=1 and i*i != num:
                factors.append(num//i)

    return sum(factors) == num

2.3 排列组合

import itertools as it

def permutation_combination(nums, need: int):
    return [list(it.permutations(each)) for each in it.combinations(nums, need)]

print(permutation_combination({1, 2, 3, 4}, 3))