# 最长连续序列
给定一个未排序的整数数组 nums ，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。
请你设计并实现时间复杂度为 O(n) 的算法解决此问题。
示例 1：
输入：nums = [100,4,200,1,3,2]
输出：4
解释：最长数字连续序列是 [1, 2, 3, 4]。它的长度为 4。
示例 2：
输入：nums = [0,3,7,2,5,8,4,6,0,1]
输出：9
提示：
0 <= nums.length <= 105-109 <= nums[i] <= 109
## 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
```