49. Group Anagrams

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

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

思路： sort each element

public class Solution {
    public List<List<String>> groupAnagrams(String[] strs) {
        List<List<String>> result = new ArrayList<List<String>>();
        HashMap<String,List<String>> map = new HashMap<String,List<String>>();
        for (int i=0;i<strs.length;i++){
            String temp = strs[i];
            char[] ch = temp.toCharArray();
            Arrays.sort(ch);
            if (map.containsKey(String.valueOf(ch))){
                map.get(String.valueOf(ch)).add(strs[i]);
            }else{
                List<String> list = new ArrayList<>();
                list.add(strs[i]);
                map.put(String.valueOf(ch),list);
            }
        }

        for (List<String> element:map.values()){
            result.add(element);
        }
        return result;
    }
}