def a(sum):
    if sum==1:
        return 1
    return sum**2+a(sum-1)
print(a(4))

3.算法

3.1冒泡

def bubblesort(a):
    leght=len(a)
    while leght>0:
        for i in range(leght-1):
            key=a[i+1]
            if key
                a[i],a[i+1]=key,a[i]
        leght=leght-1
    return a
a=[22,33,66,99,55,77,88]
print(bubblesort(a))

3.2快排

def quicksort(a):
    if len(a)<2:
        return a
    else:
        base=a[0]
        left=[i for i in a[1::] if i
        right=[i for i in a[1::] if i>base]
        return quicksort(left)+[base]+quicksort(right)
a=[3,5,29,6,9,89,456,55]
print(quicksort(a))

3.3选择

def selectsort(a):
    s=len(a)
    for i in range(0,s):
        min=i
        for j in range(i+1,s):
            if a[min]>a[j]:
                min=j
        a[min],a[i]=a[i],a[min]
    return a
a=[1,5,3,6,9,7,5,89,45,67]
print(selectsort(a))

 (￣▽￣)~*------ ٩(๑❛ᴗ❛๑)۶谢谢阅读！！！！！！！！！！！！！