#二分查找

 '''

 1.end问题

 2.44对应的end<start 找不到情况

 3.返回值递归的情况

 4,611,aim太大的情况

 '''

 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 find(l,aim,start=0,end=None):

     end = len(l) if end is None else end

     Mid_index = (end - start) // 2 +start

     if aim <= l[len(l)-1]:

         if end >= start:

             if l[Mid_index] > aim:

                 return find(l,aim,start=start,end = Mid_index-1)

             elif l[Mid_index] < aim:

                 return find(l,aim,start=Mid_index+1,end=end)

             elif l[Mid_index] == aim:

                 return Mid_index

         else:

             return '找不到!'

     else:

         return '比列表最大数都大,找不到!'

 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]

 ret = find(l,411)

 ret1 = find(l,44)

 ret2 = find(l,66)

 ret3 = find(l,67)

 print(ret,ret1,ret2,ret3)

 比列表最大数都大,找不到! 找不到! 17 18