python实现二分查找

两种方式实现：

二分查找的前提是要查找的列表已经是排过序的列表
1、使用循环方式

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def binary_find(rlist, data): len_ = len(rlist) left = 0 right = len_ - 1 while left < right: mid = (left + right) / 2 if rlist[mid] > data: right = mid - 1 elif rlist[mid] < data: left = mid + 1 else: return True return False

2、递归实现

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def binary_recursion(rlist, data):
    len_ = len(rlist)
    left = 0
    right = len_ - 1
    if len_ < 1:
        return False
    mid = (left + right) / 2
    if rlist[mid] > data:
        return binary_recursion(rlist[0:mid], data)
    elif rlist[mid] < data:
        return binary_recursion(rlist[mid+1:], data)
    else:
        return True