278-FirstBadVersion.java

// 278-First Bad Version
/* The isBadVersion API is defined in the parent class VersionControl.
      boolean isBadVersion(int version); */

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