public class Solution {
    /*
     * @param : a continuous stream of numbers
     * @param : a number
     * @return: returns the first unique number
     */
    public int firstUniqueNumber(int[] nums, int number) {
        // Write your code here
        if (nums == null || nums.length == 0) {
            return -1;
        }

        Deque<Integer> queue = new LinkedList<>();
        Set<Integer> hash = new HashSet<>();

        for (int n : nums) {
            if (hash.contains(n)) {
                // int index = queue.indexOf(n);
                // queue.remove(index);
                queue.removeFirstOccurrence(n);
            } else {
                hash.add(n);
                queue.offer(n);
            }
            if (n == number) {
                return queue.peek();
            }
        }

        return -1;
    }
};