[Leedcode 208] Implement Trie (Prefix Tree)

Trie tree, also known as the Dictionary tree and prefix tree, is a multi-fork tree for fast retrieval. The tried tree can take advantage of the common prefix of a string to conserve storage space.

However, if the system has a large number of strings without a public prefix, the corresponding trie tree will consume memory very much. (For the Trie tree on the wiki, Https://en.wikipedia.org/wiki/Trie)

1. Child nodes are represented by HashMap
2. Isword tags from the root node to whether the node represents a word, or a prefix for another word.

Implement a trie with insert , search , and startsWith methods.

classTrienode {//Initialize your data structure here.        BooleanIsword;  PublicHashmap<character,trienode>nexts;  PublicTrienode () {nexts=NewHashmap<character,trienode>(); }    } Public classTrie {PrivateTrienode Root;  PublicTrie () {root=NewTrienode (); }    //inserts a word into the trie.     Public voidInsert (String word) {intStart=0; intEnd=word.length (); Trienode P=Root;  while(start<end) {trienode node=P.nexts.get (Word.charat (start)); if(node!=NULL) {p=node; Start++; }Else  Break; }         while(start<end) {Trienode Trie=NewTrienode ();            P.nexts.put (Word.charat (start), trie); P=trie; Start++; } P.isword=true; }    //Returns If the word is in the trie.     Public BooleanSearch (String word) {Trienode P=Root;  for(intI=0;i<word.length (); i++) {Trienode child=P.nexts.get (Word.charat (i)); if(child==NULL){               return false; } P=Child ; }        returnP.isword; }    //Returns If there is any word in the trie//That's starts with the given prefix.     Public BooleanstartsWith (String prefix) {trienode p=Root;  for(intI=0;i<prefix.length (); i++) {Trienode child=P.nexts.get (Prefix.charat (i)); if(child==NULL)return false; P=Child ; }        return true; }}//Your Trie object would be instantiated and called as such://Trie Trie = new Trie ();//Trie.insert ("somestring");//trie.search ("key");

[Leedcode 208] Implement Trie (Prefix Tree)