class Solution {
    public int longestConsecutive(int[] nums) {
        Set<Integer> n = new HashSet<>();

        for (int i : nums) n.add(i);

        int longest = 0;


        for (int i : n)
        {

            if (!n.contains(i-1))
            {
                int cur = 1;
                int next = i;

                while (n.contains(next+1))
                {
                    next++;
                    cur++;
                }

                longest = Math.max(longest, cur);
            }
        }

        return longest;
    }
}