First Bad Version

    You can call to help you determine which version is the first
    bad one. The details interface can be found in the code’s annotation part.

    Example

    Given n = :

    Note

    Please read the annotation in code area to get the correct way to call
    isBadVersion in different language. For example, Java is

    Challenge

    You should call isBadVersion as few as possible.

    题解

    Python

    Java

    lower bound 的实现，这里稍微注意下lb 初始化为 0，因为 n 从1开始。ub 和 lb 分别都在什么条件下更新就好了。另外这里并未考虑 的情况。

    复杂度分析

    二分搜索，O(\log n).