49. Group Anagrams

 

Medium

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Given an array of strings, group anagrams together.

Example:

Input: ["eat", "tea", "tan", "ate", "nat", "bat"],
Output:
[
  ["ate","eat","tea"],
  ["nat","tan"],
  ["bat"]
]

Note:

• All inputs will be in lowercase.
• The order of your output does not matter.

字符串排序，当key

class Solution:
    def groupAnagrams(self, strs):
        """
        :type strs: List[str]
        :rtype: List[List[str]]
        """
        d = {}
        for s in strs:
            key = ''.join(sorted(s))
            
            if key in d:
                d[key].append(s)
            else:
                d[key] = [s]
        res = []
        for key in d:
            res.append(d[key])
        return res

c++:

class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> res ;
        unordered_map<string,vector<string>> d ;
        for(string& s :strs){
            string key = s;
            sort(key.begin(),key.end());
            d[key].push_back(s);
        }
        for(auto &item :d)
            res.push_back(item.second);
        return res;
    }
};