[Leetcode-java] Implement Trie (Prefix Tree)

Topic:

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

Your Trie object would be instantiated and called as such:
Trie Trie = new Trie ();
Trie.insert ("somestring");
Trie.search ("key");

Ideas:

The title of the topic is to implement a prefix tree, which is used to store string, so it can be understood as a 26-fork tree, in order to save each node of the child, with HashMap to store.

Also review the concept of the prefix tree, in addition to the content of a character, each node should also have a flag bit, whether it is already checked (that is, added) words.

Insert: Parses every character of a word, if present with a child that is already there, then loops to the child node, otherwise creates a new child node, and finally the character at the end of the word Isword the flag bit true;

Search: Parse each character one by one, or return FALSE if the child does not exist, or, after the loop, look at the flag of the trailing character;

Pifix: As with search, it returns true only at the end of the child map where each character is present.

Code:

classTrienode {//Initialize your data structure here.    BooleanIsword; HashMap<character, trienode>map;  PublicTrienode () {map=NewHashmap<character, trienode>(); }} Public classTrie {PrivateTrienode Root;  PublicTrie () {root=NewTrienode (); }    //inserts a word into the trie.     Public voidInsert (String word) {Char[] Charray =Word.tochararray (); Trienode Temp=Root;  for(inti = 0; i < charray.length; i++){            if(!Temp.map.containsKey (Charray[i]) temp.map.put (Charray[i],NewTrienode ());//Addtemp = Temp.map.get (Charray[i]);//go to child node            if(i = = charray.length-1)//End CharacterTemp.isword =true; }    }    //Returns If the word is in the trie.     Public BooleanSearch (String word) {Trienode temp=Root;  for(inti = 0; I < word.length (); i++) {Trienode next=Temp.map.get (Word.charat (i)); if(Next = =NULL)                return false; Temp=Next; }        returnTemp.isword; }    //Returns If there is any word in the trie//That's starts with the given prefix.     Public BooleanstartsWith (String prefix) {Trienode temp=Root;  for(inti = 0; I < prefix.length (); i++) {Trienode next=Temp.map.get (Prefix.charat (i)); if(Next = =NULL)                return false; Temp=Next; }        return true; }}

Reference Link: http://www.bubuko.com/infodetail-807921.html

[Leetcode-java] Implement Trie (Prefix Tree)