leetcode

Group Anagrams

Group Anagrams

dict solution - 172ms

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class Solution(object):
    def groupAnagrams(self, strs):
        """
        :type strs: List[str]
        :rtype: List[List[str]]
        """
        ret = {}
        for s in sorted(strs):
            key = tuple(sorted(s))
            ret[key] = ret.get(key, []) + [s]
        return ret.values()

defaultdict solution - 128ms

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import collections
class Solution(object):
	def groupAnagrams(self, strs):
	    groups = collections.defaultdict(list)
	    for s in strs:
	        groups[tuple(sorted(s))].append(s)
	    return map(sorted, groups.values())

itertools solution - 156ms

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import itertools
class Solution(object):
	def groupAnagrams(self, strs):
	    return [sorted(g) for _, g in itertools.groupby(sorted(strs, key=sorted), sorted)]

test code

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In [460]: s = Solution(); t = s.groupAnagrams(["eat","tea","tan","ate","nat","bat"])
In [461]: t
Out[461]: [['bat'], ['ate', 'eat', 'tea'], ['nat', 'tan']]

leet code

Python中collections.defaultdict()使用

理解 Python 语言中的 defaultdict