First Bad Version - 287

/* 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 low = 1;
        int high = n;
        int mid = 0;
        
        while(low < high){
            mid = low + (high-low)/2;
            
            if(isBadVersion(mid)){
                high = mid;
            }else{
                low = mid + 1;
            }
        }
        return low;
    }
}