二分查找

listA = [1,2,3,4,5,6]

def fun(arg,arg1):
    low = 0
    high = len(arg)-1
    while low <= high:
        mid = arg[(low + high) // 2]
        print(mid)
        if mid == arg1:
            return arg1
        if mid < arg1:
            low = (low+high)//2 +1
        else:
            high = (low+high)//2 -1
    return None
print(fun(listA,6))