Java for Leetcode 211 Add and Search word-data structure design

Source: Internet
Author: User

Design a data structure that supports the following and the operations:

void Addword (Word)
BOOL Search (Word)

Search (Word) can search a literal word or a regular expression string containing only letters A-Z or: A. means it can represent any one letter.

For example:

Addword ("bad")
Addword ("Dad")
Addword ("Mad")
Search ("Pad"), false
Search ("Bad")-true
Search (". Ad")-True
Search ("B..")-True
Problem Solving Ideas:

Refer to the previous Java for Leetcode 208 Implement Trie (Prefix Tree) Modification, Java implementation is as follows:

public class Worddictionary extends Trie {public void Addword (String word) {Super.insert (word);} Returns If the word is in the data structure. A word could//contain the dot character '. ' to represent any one letter.public Boolean search (String word) {if (Word = = N ull | | Word.length () = = 0) return False;return search (Word, 0, root);} public boolean search (String word, int depth, Trienode node) {if (depth = = Word.length ()-1) {if (Word.charat (depth)! = ') .‘)  {if (Node.son[word.charat (depth)-' a ']! = null) {node = Node.son[word.charat (Depth)-' a '];return node.isend;} elsereturn false;} for (int i = 0; i <; i++) {if (node.son[i]! = null) {Trienode Ason = node.son[i];if (ason.isend) return true;}} return false;} if (Word.charat (depth)! = '. ')  {if (Node.son[word.charat (depth)-' a ']! = null) {node = Node.son[word.charat (Depth)-' A '];return search (Word, depth + 1, node);} Elsereturn false;} for (int i = 0; i <; i++) {if (node.son[i]! = null) {Trienode Ason = node.son[i];if (Search (Word, depth + 1, Ason)) return true;}} return false;}} Class Trienode {//Initialize your data structure Here.int num;//How many words are passed through this node, that is, the number of occurrences of the node character trienode[] son;//all sons node Boolean I send;//is not the value of the last node Char val;//node Trienode () {this.num = 1;this.son = new Trienode[26];this.isend = false;}} Class Trie {protected Trienode root;public Trie () {root = new Trienode ();} public void Insert (String word) {if (Word = = NULL | | word.length () = = 0) return; Trienode node = this.root;char[] Letters = Word.tochararray (); for (int i = 0; i < word.length (); i++) {Int. POS = Letter S[i]-' a ', if (node.son[pos] = = null) {Node.son[pos] = new Trienode (); node.son[pos].val = Letters[i];} else {Node.son[pos] . num++;} node = Node.son[pos];} Node.isend = true;} Returns If the word is in the Trie.public boolean search (String word) {if (Word = = NULL | | word.length () = = 0) {return false;} Trienode node = root;char[] Letters = Word.tochararray (); for (int i = 0; i < word.length (); i++) {int pos = letters[i] -' a '; if (node.son[pos] = null) {node = Node.son[pos];} else {return false;}} return node.isend;} Returns If there is any word in the trie//this starts with the given Prefix.public boolean startsWith (String prefix) { if (prefix = = NULL | | prefix.length () = = 0) {return false;} Trienode node = root;char[] Letters = Prefix.tochararray (); for (int i = 0; i < prefix.length (); i++) {int pos = letters [i]-' a '; if (node.son[pos]! = null) {node = Node.son[pos];} else {return false;}} return true;}} Your Trie object would be instantiated and called as such://Trie Trie = new Trie ();//Trie.insert ("somestring");//Trie . Search ("key");

Java for Leetcode 211 Add and Search word-data structure design

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