First Bad Version - Easy Python Binary Search Interview Problem

You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad.

You are given an API isBadVersion(version) which returns whether version is bad. Implement a function to find the first bad version. You should minimize the number of calls to the API.

Example 1

Input: n = 5, bad = 4
Output: 4
Explanation: isBadVersion(3) -> False, isBadVersion(5) -> True, isBadVersion(4) -> True. Version 4 is the first bad version.

Example 2

Input: n = 1, bad = 1
Output: 1
Explanation: Version 1 is the only version and it is bad, so it is the first bad version.

Constraints

1 <= bad <= n <= 2^31 - 1

Hints