# 最长连续序列

<p>给定一个未排序的整数数组 <code>nums</code> ，找出数字连续的最长序列（不要求序列元素在原数组中连续）的长度。</p>

<p>请你设计并实现时间复杂度为 <code>O(n)</code><em> </em>的算法解决此问题。</p>

<p> </p>

<p><strong>示例 1：</strong></p>

<pre>
<strong>输入：</strong>nums = [100,4,200,1,3,2]
<strong>输出：</strong>4
<strong>解释：</strong>最长数字连续序列是 <code>[1, 2, 3, 4]。它的长度为 4。</code></pre>

<p><strong>示例 2：</strong></p>

<pre>
<strong>输入：</strong>nums = [0,3,7,2,5,8,4,6,0,1]
<strong>输出：</strong>9
</pre>

<p> </p>

<p><strong>提示：</strong></p>

<ul>
	<li><code>0 <= nums.length <= 10<sup>5</sup></code></li>
	<li><code>-10<sup>9</sup> <= nums[i] <= 10<sup>9</sup></code></li>
</ul>


## template

```python

class Solution:
    def longestConsecutive(self, nums: List[int]) -> int:
        hash_dict = {}

        max_length = 0

        for num in nums:

            if num not in hash_dict:

                pre_length = hash_dict.get(num - 1, 0)
                next_length = hash_dict.get(num + 1, 0)

                cur_length = pre_length + 1 + next_length

                if cur_length > max_length:
                    max_length = cur_length

                hash_dict[num] = cur_length
                hash_dict[num - pre_length] = cur_length
                hash_dict[num + next_length] = cur_length

        return max_length

```

## 答案

```python

```

## 选项

### A

```python

```

### B

```python

```

### C

```python

```