The code base version is an integer start from 1 to n. One day, someone committed a bad version in the code case, so it caused this version and the following versions are all failed in the unit tests. Find the first bad version.

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

Notice

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

Have you met this question in a real interview?

Yes

Example

Given n =5:

isBadVersion(3) -
>
 false
isBadVersion(5) -
>
 true
isBadVersion(4) -
>
 true

Here we are 100% sure that the 4th version is the first bad version.

Challenge

You should call_isBadVersion_as few as possible.

/**

* class SVNRepo {

* public:

* static bool isBadVersion(int k);

* }

* you can use SVNRepo::isBadVersion(k) to judge whether

* the kth code version is bad or not.

*/

class Solution {

public:

/\*\*

 \* @param n: An integers.

 \* @return: An integer which is the first bad version.

 \*/

int findFirstBadVersion\(int n\) {

    // write your code here

    int start = 1, end = n;

    while \(start + 1 < end\) {

        int mid = \(end - start\) / 2 + start;

        if \(SVNRepo::isBadVersion\(mid\)\) {

            end = mid;

        } else {

            start = mid;

        }

    }

    if \(SVNRepo::isBadVersion\(start\)\) {

        return start;

    }

    return end;

}

};

results matching ""

    No results matching ""