LeetCode 筆記 - 278-First-Bad-Version

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題目在此 278. First Bad Version

給正整數 n，找出 1 ~ n 第一個壞掉的版本

解題思維

利用 Binary Search 來快速搜尋就可以了

完成✅

程式碼

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# The isBadVersion API is already defined for you.
# def isBadVersion(version: int) -> bool:

class Solution:
    def firstBadVersion(self, n: int) -> int:
        
        if n == 1:
            return 1
        
        start = 0
        end = n
        
        while start <= end:
            mid = int((start + end) / 2)
            
            if isBadVersion(mid):
                end = mid - 1
            elif isBadVersion(mid + 1):
                return mid + 1
            else:
                start = mid + 1
        
        return -1

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