leetcode Group Anagrams

对字符串对象进行分组,相同字母组成的字符串，排序出来的值肯定是一样的，然后以这个值为key,存放对应的相同字母拼接成的字符串数组

public class GroupAnagrams {
    public static List<List<String>> groupAnagrams(String[] strs) {
        if (strs.length == 0) return new ArrayList();
        Map<String, List> ans = new HashMap<String, List>();
        for (String s : strs) {
            char[] ca = s.toCharArray();
            Arrays.sort(ca);
            String key = String.valueOf(ca);
            if (!ans.containsKey(key)) ans.put(key, new ArrayList());
            ans.get(key).add(s);
        }
        return new ArrayList(ans.values());
    }

    public static void main(String []args){
        String [] strs = new String[]{"eat", "tea", "tan", "ate", "nat", "bat"};
        groupAnagrams(strs);


    }
}