142 lines
4.2 KiB
Java
142 lines
4.2 KiB
Java
package DataStructures.Trees;
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/**
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* Trie Data structure implementation without any libraries
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*
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* @author Dheeraj Kumar Barnwal (https://github.com/dheeraj92)
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*/
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import java.util.Scanner;
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public class TrieImp {
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public class TrieNode {
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TrieNode[] child;
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boolean end;
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public TrieNode() {
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child = new TrieNode[26];
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end = false;
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}
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}
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private final TrieNode root;
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public TrieImp() {
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root = new TrieNode();
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}
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public void insert(String word) {
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TrieNode currentNode = root;
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for (int i = 0; i < word.length(); i++) {
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TrieNode node = currentNode.child[word.charAt(i) - 'a'];
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if (node == null) {
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node = new TrieNode();
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currentNode.child[word.charAt(i) - 'a'] = node;
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}
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currentNode = node;
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}
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currentNode.end = true;
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}
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public boolean search(String word) {
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TrieNode currentNode = root;
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for (int i = 0; i < word.length(); i++) {
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char ch = word.charAt(i);
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TrieNode node = currentNode.child[ch - 'a'];
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if (node == null) {
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return false;
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}
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currentNode = node;
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}
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return currentNode.end;
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}
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public boolean delete(String word) {
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TrieNode currentNode = root;
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for (int i = 0; i < word.length(); i++) {
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char ch = word.charAt(i);
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TrieNode node = currentNode.child[ch - 'a'];
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if (node == null) {
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return false;
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}
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currentNode = node;
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}
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if (currentNode.end == true) {
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currentNode.end = false;
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return true;
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}
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return false;
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}
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public static void sop(String print) {
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System.out.println(print);
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}
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/**
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* Regex to check if word contains only a-z character
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*/
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public static boolean isValid(String word) {
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return word.matches("^[a-z]+$");
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}
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public static void main(String[] args) {
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TrieImp obj = new TrieImp();
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String word;
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@SuppressWarnings("resource")
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Scanner scan = new Scanner(System.in);
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sop("string should contain only a-z character for all operation");
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while (true) {
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sop("1. Insert\n2. Search\n3. Delete\n4. Quit");
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try {
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int t = scan.nextInt();
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switch (t) {
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case 1:
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word = scan.next();
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if (isValid(word))
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obj.insert(word);
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else
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sop("Invalid string: allowed only a-z");
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break;
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case 2:
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word = scan.next();
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boolean resS = false;
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if (isValid(word))
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resS = obj.search(word);
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else
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sop("Invalid string: allowed only a-z");
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if (resS)
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sop("word found");
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else
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sop("word not found");
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break;
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case 3:
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word = scan.next();
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boolean resD = false;
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if (isValid(word))
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resD = obj.delete(word);
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else
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sop("Invalid string: allowed only a-z");
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if (resD) {
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sop("word got deleted successfully");
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} else {
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sop("word not found");
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}
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break;
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case 4:
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sop("Quit successfully");
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System.exit(1);
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break;
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default:
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sop("Input int from 1-4");
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break;
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}
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} catch (Exception e) {
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String badInput = scan.next();
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sop("This is bad input: " + badInput);
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}
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}
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}
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}
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