128. 最长连续序列

题解

哈希表的妙用 绝了

class Solution {
    public int longestConsecutive(int[] nums) {
        HashSet<Integer> set = new HashSet<>();
        int res = 0;
        for (int var : nums){
            set.add(var);
        }
        while (!set.isEmpty()){
            Integer mid = set.iterator().next();
            int pre = mid - 1; int next = mid + 1;
            set.remove(mid);
            while (set.contains(pre)){
                set.remove(pre--);
            }
            while (set.contains(next)){
                set.remove(next++);
            }
            res = Math.max(res, next - pre - 1);
        }
        return res;
    }
}