使用python实现数据结构算法

二分查找

def binary_search(list, item):
    low = 0
    high = len(list) - 1
    while(low <= high):
        mid = (low + high) // 2
        guess = list[mid]
        if guess == item:
            return mid
        elif guess > item:
            high = mid - 1
        elif guess < item:
            low = mid + 1
    return None