63 lines
1.6 KiB
Java
63 lines
1.6 KiB
Java
package com.baeldung.trie;
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class Trie {
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private TrieNode root;
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Trie() {
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root = new TrieNode();
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}
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void insert(String word) {
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TrieNode current = root;
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for (char l : word.toCharArray()) {
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current = current.getChildren().computeIfAbsent(l, c -> new TrieNode());
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}
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current.setEndOfWord(true);
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}
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boolean delete(String word) {
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return delete(root, word, 0);
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}
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boolean containsNode(String word) {
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TrieNode current = 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 = current.getChildren().get(ch);
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if (node == null) {
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return false;
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}
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current = node;
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}
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return current.isEndOfWord();
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}
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boolean isEmpty() {
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return root == null;
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}
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private boolean delete(TrieNode current, String word, int index) {
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if (index == word.length()) {
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if (!current.isEndOfWord()) {
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return false;
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}
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current.setEndOfWord(false);
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return current.getChildren().isEmpty();
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}
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char ch = word.charAt(index);
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TrieNode node = current.getChildren().get(ch);
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if (node == null) {
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return false;
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}
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boolean shouldDeleteCurrentNode = delete(node, word, index + 1) && !node.isEndOfWord();
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if (shouldDeleteCurrentNode) {
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current.getChildren().remove(ch);
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return current.getChildren().isEmpty();
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}
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return false;
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}
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}
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