LeetCode 278. First Bad Version

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本文介绍了一种使用二分查找算法来高效确定首次出现故障的产品版本的方法。在一个由连续版本号构成的序列中，一旦某个版本开始出现故障，其后所有版本都将受到影响。通过调用一个布尔型API isBadVersion(version)，可以判断指定版本是否为故障版本。文章提供了一个示例代码，展示如何快速找到首个故障版本，以最小化API调用次数。

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 will return whether version is bad. Implement a function to find the first bad version. You should minimize the number of calls to the API.

Binary Search of the left most 1.

    int firstBadVersion(int n) {
        int left = 1, right = n;
        while(left < right) {
            int mid = left + (right - left) / 2;
            if(isBadVersion(mid) == 0) left = mid + 1;
            else right = mid;
        }
        if(isBadVersion(left)) return left;
        return -1;
    }