class​ ​TrieNode​ ​{
    Map<Character,​ ​TrieNode>​ ​children;​ ​​ ​​ ​​ ​//​ ​map​ ​the​ ​character​ ​to​ ​the​ ​corresponding​ ​child
    boolean​ ​isEnd;
}