Lintcode-first Bad Version

The code base version is a integer and start from 1 to N. One day, someone commits a bad version of the code case, so it caused itself and the following versions is all failed in t He unit tests.

You can determine whether a version was bad by the following interface:

 java: 
     public VersionControl {
     } 
 c++: 
     class VersionControl {
     public: 
         bool isbadversion (int version); 
     }; 
 python: 
     class VersionControl: 
 

Find the first bad version.

Note

You should call Isbadversion as few as possible.

Please read the annotation in code area to get the correct-on-the-isbadversion in different language. For example, Java is versioncontrol.isbadversion.

Example

Given n=5

Call Isbadversion (3), Get false

Call Isbadversion (5), Get True

Call Isbadversion (4), Get True

Return 4 is the first bad version

Challenge

Don't call isbadversion exceed O (Logn) times.

Solution:

1 /**2 * public class VersionControl {3 * public static Boolean isbadversion (int k);4  * }5 * can use Versioncontrol.isbadversion (k) to judge wether6 * The KTH code version is bad or not.7 */8 classSolution {9     /**Ten      * @paramn:an integers. One      * @return: An integer which are the first bad version. A      */ -      Public intFindfirstbadversion (intN) { -         if(n==1)return1; the  -         intStart = 1; -         intEnd =N; -          while(start<=end) { +             intMID = start + (End-start)/2; -  +             if(!Versioncontrol.isbadversion (mid)) AStart = Mid +1; at             Else { -                 if(Mid==1 | |! Versioncontrol.isbadversion (mid-1)) -                     returnmid; -                 ElseEnd = Mid-1; -             } -         } in  -         return-1; to     } +}

Lintcode-first Bad Version