islessthan Interview

IsLessThan.java

/**
 * Created by Readman on 7/22/14.
 */
public class IsLessThan {
    int x;
    public int BS(int[] A, int x){
        this.x = x;
        return rec(A, x, 0, A.length-1);
    }
    public int rec(int[] A, int x, int start, int end) {
        if (start > end)
            return -1;
        int mid = start + (end - start) / 2;
        if (A[mid] == x)
            return mid;
        if (isLessThanX(A[mid])){
            return rec(A, x, mid+1, end);
        } else{
            return rec(A, x, start, mid-1);
        }
    }
    public boolean isLessThanX(int y){
        return y<x;
    }

    public static void main(String[] args) {
        IsLessThan isLessThan = new IsLessThan();
        System.out.println(isLessThan.BS(new int[]{1,3,5,7,9}, 7));
    }
}