LeetCode First Bad Version

 1 /* The isBadVersion API is defined in the parent class VersionControl.
 2       boolean isBadVersion(int version); */
 3 
 4 public class Solution extends VersionControl {
 5     public int firstBadVersion(int n) {
 6         int left = 1;
 7         int right = n;
 8         int res = 0;
 9         while(left<=right){
10             int mid = left + (right - left)/2;
11             if(isBadVersion(mid)){
12                 right = mid-1;
13             }else{
14                 left = mid+1;
15             }
16         }
17         return left;
18     }
19 }