最长连续序列_longest_consecutive_128

class Solution {
    public int longestConsecutive(int[] nums) {
        // 利用hashset进行去重
        HashSet<Integer> num_set = new HashSet<>();
        for (int num : nums) {
            num_set.add(num);
        }
        // 记录最长
        int longestStreak = 0;
        for (Integer num : num_set) {
            //判断左边连续值是否存在
            if (!num_set.contains(num - 1)){
                int currentNum = num;
                int currentSteak = 1;
                //判断右边连续值是否存在
                while (num_set.contains(currentNum + 1)){
                    currentNum += 1;
                    currentSteak += 1;
                }
                longestStreak = Math.max(currentSteak,longestStreak);
            }
        }
        return longestStreak;
    }
}