First Bad Version Leetcode Solution

Hello coders, If you are looking for the solution to the First Bad Version of the Leetcode problem. Then you’ve reached the right place.

Today, In this blog I will give a java solution for this problem. But before that let’s see the problem statement.

Problem statement:

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.

Example 1:

Input: n = 5, bad = 4
Output: 4
call isBadVersion(3) -> false
call isBadVersion(5) -> true
call isBadVersion(4) -> true
Then 4 is the first bad version.

Example 2:

Input: n = 1, bad = 1
Output: 1


  • 1 <= bad <= n <= 231 - 1
//First Bad Version Leetcode Solution
public class Solution extends VersionControl {
    public int firstBadVersion(int n) {
        int low=1;
        int high=n;
            int mid=low+(high-low)/2;
            if(isBadVersion(mid)) high=mid;
        return low;

//First Bad Version Leetcode Solution

Disclaimer: This problem(First Bad Version Leetcode solution) is originally created by LeetcodeCodesagar only provides a solution for it. This solution is only for Educational and learning purposes.

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