[LeetCode] 49. Group Anagrams 分组变位词

Posted 2020-10-26 轻风舞动

Given an array of strings, group anagrams together.

For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], 
Return:

[
  ["ate", "eat","tea"],
  ["nat","tan"],
  ["bat"]
] 

Note: All inputs will be in lower-case.

给一个含字符串的数组，字符串是变位词的分在一组，返回所有分组。变位词就是一个单词通过改变单词当中的字母顺序变成另外一个单词。

Java：

public List<List<String>> groupAnagrams(String[] strs){  
    List<List<String>> lists=new ArrayList<List<String>>();  
    Map<String,List<String>> map=new HashMap<String,List<String>>();  
    for(String str:strs){  
        char[] chs=str.toCharArray();  
        Arrays.sort(chs);  
        String tmp=new String(chs);  
        if(map.containsKey(tmp))  
            map.get(tmp).add(str);  
        else{  
            List<String> list=new ArrayList<String>();  
            list.add(str);  
            map.put(tmp, list);  
        }  
    }  
    for(String str:map.keySet()){  
        lists.add(map.get(str));  
    }  
    return lists;  
}

Java:

public class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
        Map<String, List<String>> map = new HashMap<>();
        for (String s : strs) {
            char[] sc = s.toCharArray();
            Arrays.sort(sc);
            String key = String.valueOf(sc);
            map.putIfAbsent(key, new ArrayList<>());
            map.get(key).add(s);
        }
        return new ArrayList<>(map.values());
    }
}

Python：HashMap

class Solution(object):
    def groupAnagrams(self, strs):
        anagrams_map, result = collections.defaultdict(list), []

        for s in strs:
            sorted_str = ("").join(sorted(s))
            anagrams_map[sorted_str].append(s)

        for anagram in anagrams_map.values():
            anagram.sort()
            result.append(anagram)
        return result

C++：

class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> res;
        unordered_map<string, vector<string>> m;
        for (string str : strs) {
            string t = str;
            sort(t.begin(), t.end());
            m[t].push_back(str);
        }
        for (auto a : m) {
            res.push_back(a.second);
        }
        return res;
    }
};

C++：Array

class Solution {
public:
    vector<vector<string>> groupAnagrams(vector<string>& strs) {
        vector<vector<string>> res;
        unordered_map<string, vector<string>> m;
        for (string str : strs) {
            vector<int> cnt(26, 0);
            string t = "";
            for (char c : str) ++cnt[c - ‘a‘];
            for (int d : cnt) t += to_string(d) + "/";
            m[t].push_back(str);
        }
        for (auto a : m) {
            res.push_back(a.second);
        }
        return res;
    }
};