Day1_First_Bad_Version.java

public class Solution extends VersionControl {
    public int firstBadVersion(int n) 
    {
        int start = 0, end = n - 1;
        while (start <= end) 
        {
            int mid = start + (end - start) / 2;
            if (isBadVersion(mid)) 
                end = mid - 1;
            else 
                start = mid + 1;
        }
        return start;
    }
}