题解 | #字母异位词分组#

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param strs string字符串一维数组 
     * @return string字符串二维数组
     */
    public String[][] groupAnagrams (String[] strs) {



        List<List<String>> ans = new ArrayList<>();
        HashMap<String, Integer> map = new HashMap<>();
        for (String str : strs) {
            char[] cs = str.toCharArray();
            Arrays.sort(cs);
            String temp = new String(cs);
            if (!map.containsKey(temp)){
                List<String> list = new ArrayList<>();
                list.add(str);
                ans.add(list);
                map.put(temp, ans.size() - 1);
            }else {

                ans.get(map.get(temp)).add(str);
            }
        }
        String[] res[] = new String[ans.size()][];
        for (int i = 0; i < ans.size(); i++) {
            String[] resEle = new String[ans.get(i).size()];
            for (int j = 0; j < ans.get(i).size(); j++) {
                resEle[j] = ans.get(i).get(j);
            }
            res[i] = resEle;
        }
        return res;
    }
}