力扣Hot100题解之哈希表Python实现详解

一、1. 两数之和

class Solution:
	def twoSum(self, nums, target):
		sub_data = {}
		for idx, x in enumerate(nums):
			if target-x in sub_data:
				return [idx, sub_data[target-x]]
			sub_data[x] = idx

二、49. 字母异位词分组

class Solution:
    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
        dict_s = collections.defaultdict(list)
        for s in strs:
            list_s = "".join(sorted(s))
            dict_s[list_s].append(s)
        res = []
        for i in dict_s:
            res.append(dict_s[i])
        return res

三、128. 最长连续序列

class Solution:
	def longestConsecutive(self, nums):
		long_seq = 0
		num_set = set(nums)  # 这里就是利用字典去重，减少点运算
		for n in nums:
			if n-1 not in num_set:
				cur_num = n
				cur_long_seq = 1
				while cur_num + 1 in num_set:
					cur_num += 1
					cur_long_seq += 1
				long_seq = max(long_seq, cur_long_seq)
		return long_seq

作者：Y1nhl