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First Bad Version (Practice)

Question

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.

Suppose you have n versions [1, 2, ..., n] and you want to find out the first bad one, which causes all the following ones to be bad.

You are given an API bool 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.

Leetcode

Implementation

Question mascarading as 🔑Find the First True in a Sorted Boolean Array , instead of a True value in an array it returns that from an API.

Regular Approach

class Solution:
    def firstBadVersion(self, n: int) -> int:
        
        left, right = 0,n
        possibleValue = -1
        
        
        while left <= right:
            
            mid = left + (right-left)//2
            PotentialTrue = isBadVersion(mid)

	
            if PotentialTrue:
                possibleValue = mid
                right = mid -1
            
            else:
                left = mid + 1
                
        return possibleValue

Alternate Approach (Optional)

class Solution:
    def firstBadVersion(self, n: int) -> int:
        
        left, right = 0,n
      
        while left < right:
            
            mid = left + (right-left)//2
            PotentialTrue = isBadVersion(mid)
	
            if PotentialTrue:
                right = mid
            
            else:
                left = mid + 1
                
        return right if isBadVersion(right) == True else -1