Anagram

49 Given an array of strings, return all groups of strings that are anagrams.

Use hast to store sorted string

• Time: O(N*KlogK)

• Space: O(N*K)

public List<String> anagrams(String[] strs) {
    HashMap<String, List<String>> map = new HashMap<>();
    for (int i = 0; i < strs.length; i++){
        char[] tmp = strs[i].toCharArray();
        Arrays.sort(tmp);
        String key = new String(tmp);
        if (!map.containsKey(key)){
            map.put(key, new ArrayList<String>());
        }
        map.get(key).add(strs[i]);
    }

    List<String> ans = new ArrayList<>();
    for (List<String> tmp : map.values()){
        if (tmp.size() >= 2){
            ans.addAll(tmp);
        }
    }
    return ans;
}