Python 实现二分查找算法

def search1(sequence, number):
    lower = 0
    upper = len(sequence) - 1

    while lower <= upper:
        mid = (lower + upper) // 2
        if number > sequence[mid]:
            lower = mid + 1
        elif number < sequence[mid]:
            upper = mid - 1
        else:
            return mid
    return -1

def search(sequence, number, lower, upper):
    if lower == upper:
        assert number == sequence[upper]
        return upper
    else:
        middle = (lower + upper) // 2
        if number > sequence[middle]:
            return search(sequence, number, middle + 1, upper)
        else:
            return search(sequence, number, lower, middle)