Python——递归、二分查找算法

n = 0
def story():
    global n
    n+= 1
    print(n)
    story()     #997/998
story()

import sys
sys.setrecursionlimit(2000) #1997/1998

# 算年龄

def age(n):
    if n == 4:
        return 40
    elif n>0 and n<4:
        return age(n+1) + 2

print(age(1))

# 学着看递归
‘‘‘
def age(1): #46
    if 1 == 4:
        return 40
    elif 1>0 and 1<4:
        return age(2) + 2   #44+2 = 46

def age(2): #44
    if 2 == 4:
        return 40
    elif 2>0 and 2<4:
        return age(3) + 2   #42+2 = 44

def age(3): #42
    if 3 == 4:
        return 40
    elif 3>0 and 3<4:
        return age(4) + 2   #40+2 = 42

def age(4): #40
    if 4 == 4:
        return 40
    elif 4>0 and 4<4:
        return age(4+1) + 2
‘‘‘

l = [2,3,5,10,15,16,18,22,26,30,32,35,41,42,43,55,56,66,67,69,72,82,83,88]
def find(l,aim,start = 0,end=None):
    end = len(l) if end is None else end
    mid_index = (end - start) // 2 + start  #计算中简值
    if start <= end:
        if l[mid_index] < aim:
            l[mid_index + 1:]
            return find(l, aim, start=mid_index + 1, end=end)
        elif l[mid_index] > aim:
            return find(l, aim, start=start, end=mid_index - 1)
        else:
            return mid_index
            # print(‘找到了‘, mid_index, aim)
    else:
        return ‘找不到这个值啊‘
ret1 = find(l,67)  
ret2 = find(l,64) 

print(ret1) #找到了 18 
print(ret2) #找不到这个值啊