LeetCode--Longest Consecutive Sequence（最长连续序列） Python

题目描述：

　　Longest Consecutive Sequence（最长连续序列）

中文：

给定一个未排序的整数数组，找出最长连续序列的长度。

要求算法的时间复杂度为 O(n)。

英文：

Given an unsorted array of integers, find the length of the longest consecutive elements sequence.

Your algorithm should run in O(n) complexity.

class Solution(object):
    def longestConsecutive(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        Dict = {}
        for i in nums:
            Dict[i] = 1
        List = Dict.keys()
        count_max = 0
        while(len(Dict)):
            List = Dict.keys()
            count = 1
            temp_left = List[0]
            temp_right = List[0]
            Dict.pop(temp_left)
            while(1):
                if temp_left-1 in Dict and temp_right+1 in Dict:
                    count = count+2
                    temp_left = temp_left-1
                    temp_right = temp_right+1
                    Dict.pop(temp_left)
                    Dict.pop(temp_right)
                    continue
                elif temp_left-1 not in Dict and temp_right+1 in Dict:
                    count = count+1
                    temp_right = temp_right+1
                    Dict.pop(temp_right)
                    continue
                elif temp_left-1 in Dict and temp_right+1 not in Dict:
                    count = count+1
                    temp_left = temp_left-1
                    Dict.pop(temp_left)
                    continue
                else:
                    if count>count_max:
                        count_max=count
                        break
                    else:
                        break
        return count_max

题目来源：力扣