力扣 | 49. 字母异位词分组

这里使用HashMap

在这里插入图片描述

Java

package _49;import java.util.*;public class Problem_49_GroupAnagrams {public List<List<String>> groupAngrams(String [] strs){Map<String,List<String>> map = new HashMap<>();
//        int [] arr = new int[]{};for(String s : strs){char[] chars = s.toCharArray();Arrays.sort(chars);//排序之后的字母异位词都是一样，因此可以作为map的keyString key = String.valueOf(chars);if(!map.containsKey(key)) map.put(key,new ArrayList<>());map.get(key).add(s);}return new ArrayList<>(map.values());//}}public List<List<String>> groupAnagrams1(String[] strs) {Map<String, List<String>> map = new HashMap<>();for (String s : strs) {char[] chars = s.toCharArray();int[] count = new int[26];for (char c : chars) count[c - 'a']++;String key = Arrays.toString(count);//int: 32位有符号整数，范围是-2^31到2^31-1。if (!map.containsKey(key)) map.put(key, new ArrayList<>());map.get(key).add(s);}return new ArrayList<>(map.values());}

C++

class Solution {
public:vector<vector<string>> groupAnagrams(vector<string>& strs) {unordered_map<string, vector<string>> map;for (string& str : strs) {vector<int> count(26);for (char c : str) count[c - 'a']++;string key = "";for (int i = 0; i < 26; i++) key += count[i];map[key].emplace_back(str);}vector<vector<string>> ans;for (auto it = map.begin(); it != map.end(); ++it) {ans.emplace_back(it->second);}return ans;}vector<vector<string>> groupAnagrams1(vector<string>& strs) {unordered_map<string, vector<string>> map;for (string& str : strs) {string key = str;sort(key.begin(), key.end());map[key].emplace_back(str);}vector<vector<string>> ans;for (auto it = map.begin(); it != map.end(); ++it) {ans.emplace_back(it->second);}return ans;}
};