递归,二分查找

递归,自己调用自己

二分查找就是 一半一半的查找

递归写二分查找

l2 = [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_index(lis,aim,star=0,end=None):
    end = len(lis) - 1 if end is None else end
    median = (end-star) // 2 +star
    if star <= end:
        if aim > lis[median]:
            return two_index(lis,aim ,star=median+1,end=end)
        if aim < lis[median]:
            return two_index(lis,aim,star=star,end=median-1)
        if aim == lis[median]:
            return median
    else:
        return None
print(two_index(l2,100))

while 写二分查找

l2 = [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_index(lis,aim):
    star=0
    end=len(lis)-1
    while star <= end:
        median = (star + end) // 2
        if  aim == lis[median] :
            return median
        elif  aim  > lis[median]:
            star = median + 1
        elif aim < lis[median]:
            end= median -1
    return '查无此人'
print(two_index(l2,66))