Given a sorted array of unique positive and negative numbers, find if there is an index i such that A[i] = i

IndexElement.java

public class IndexElementArray {
    public static void main(String[] args) {
        System.out.println(indexElement(new int[] {-5, -3, 0, 3, 5})); //Expect True
        System.out.println(indexElement(new int[] {-5, -3, 0, 1, 2})); //Expect false
        System.out.println(indexElement(new int[] {0, 2, 3, 4, 5})); //Expect True
        System.out.println(indexElement(new int[] {-1, 0, 1, 2, 4})); //Expect True
        System.out.println(indexElement(new int[] {-10, 10, 20, 30, 40})); //Expect false
    }

    private static boolean indexElement(int []arr) {
        if (arr == null || arr.length == 0) {
            return false;
        }
        int low = 0, high = arr.length - 1;
        int mid = 0;

        while(low <= high) {
            mid = (low + high) / 2;
            if(arr[mid] == mid) {
                return true;
            } else if(arr[mid] < mid) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return false;
    }
}