数据结构与算法 查找 二分查找

def search(alist,item):
    find=False
    low=0
    high=len(alist)-1

    while low<=high:
        # 中间位置的索引
        mid=(low+high)//2
        if alist[mid]>item:
            high=mid-1
        elif alist[mid]<item:
            low=mid+1
        # 找到该位置
        else:
            find=True
            break
    return find

alist=[1,2,5,7,8]
print(search(alist,8))