class Solution:
    def longestConsecutive(self, nums: List[int]) -> int:
        numSet = set(nums)
        maxSeqLen = 0
        while maxSeqLen < len(numSet):
            num = numSet.pop()
            longest = num+1
            while longest in numSet:
                numSet.remove(longest)
                longest += 1
            num = num-1
            while num in numSet:
                numSet.remove(num)
                num -= 1
            maxSeqLen = max(maxSeqLen, longest-num-1)
        return maxSeqLen

public int longestConsecutive(int[] nums) {
    if (nums.length == 0) { return 0; }
    Arrays.sort(nums);
    int max = 1;
    int count = 1;
    for (int i=1; i<nums.length; i++) {
        if (nums[i] == nums[i-1] + 1) {
            count++;
        } else if (nums[i] == nums[i-1]) {
            continue;
        } else {
            max = Math.max(count, max);
            count = 1;
        }
    }
    return Math.max(count,max);
}

public int longestConsecutive2(int[] nums) {
    Set<Integer> set = new HashSet<>();
    for (int num : nums) {
        set.add(num);
    }

    int maxCount = 0;
    for (int num: nums) {
        if (!set.contains(num-1)) {
            int count = 1;
            while (set.contains(++num)) {
                count++;
            }
            maxCount = Math.max(count, maxCount);
        }
    }
    return maxCount;
}