递归与二分法

递归：在一个函数内再调用这个函数本身
递归的最大深度是997，可以在sys里面修改

def hannuo(n,a,b,c):
    if n == 1:
        print(a,'-->',c)
    else:
        hannuo(n-1,a,c,b)#把n-1层放到b
        print(a,'-->',c)#把最后一层放到c
        hannuo(n-1,b,a,c)#把b上的n-1层放到c

n = int(input('please input one number'))
hannuo(n,'a','b','c')

二分法

l = [2,3,5,10,15,16,18,22,26,30,32,35,41,42,43,55,56,66,67,69,72,76,82,83,88]

def two_search(l):
    n = len(l)
    a = int(input('please input a number'))
    left = 0
    right = n
    while left <= right:
        if l[(left+right)//2] < a:
            left = (left+right)//2
        elif l[(left+right)//2] > a:
            right = (left+right)//2
        elif l[(left+right)//2] == a:
            print('找到了',(left+right)//2+1)
            break

two_search(l)