Java examples for Data Structure:Tree
Search Tree
package com.company.stucts.binarytree.searchtree; import java.util.Comparator; @SuppressWarnings({ "Duplicates", "WeakerAccess" }) public class SearchTree<K, V> { private Node<K, V> rootNode; private final Comparator<K> comparator; public SearchTree(Comparator<K> comparator) { this.comparator = comparator; }/*from w w w. ja va2s.c om*/ public void add(K key, V value) { Node<K, V> node = rootNode; Node<K, V> parentNode = null; while (node != null) { int result = comparator.compare(key, node.key); if (result == 0) { node.value = value; return; } else { parentNode = node; if (result < 0) { node = node.left; } else { node = node.right; } } } Node<K, V> newNode = new Node<>(key, value); if (parentNode == null) { rootNode = newNode; } else { if (comparator.compare(key, parentNode.key) < 0) { parentNode.left = newNode; } else { parentNode.right = newNode; } } } public V getValue(K key) { Node<K, V> node = rootNode; while (node != null) { int result = comparator.compare(key, node.key); if (result == 0) { return node.value; } if (result < 0) { node = node.left; } else { node = node.right; } } return null; } public void remove(K key) { Node<K, V> node = rootNode; Node<K, V> parentNode = null; // search node while (node != null) { int result = comparator.compare(key, node.key); if (result == 0) { break; } parentNode = node; if (result < 0) { node = node.left; } else { node = node.right; } } // node not find if (node == null) { return; } if (node.right == null) { if (parentNode == null) { // change root node rootNode = node.left; } else { // change parent node if (node == parentNode.left) { parentNode.left = node.left; } else { parentNode.right = node.left; } } } else { Node<K, V> mostLeftNode = node.right; parentNode = null; while (mostLeftNode.left != null) { parentNode = mostLeftNode; mostLeftNode = mostLeftNode.left; } node.value = mostLeftNode.value; node.key = mostLeftNode.key; if (parentNode != null) { parentNode.left = mostLeftNode.right; } else { node.right = mostLeftNode.right; } } } public void printTree() { printNode(rootNode); } private void printNode(Node<K, V> node) { System.out.println("Node: [" + node.key + "," + node.value + "]"); if (node.left != null) { printNode(node.left); } if (node.right != null) { printNode(node.right); } } private static class Node<K, V> { private K key; private V value; private Node<K, V> left, right; Node(K key, V value) { this.key = key; this.value = value; } } /** * Test main method */ public static void main(String[] args) { Comparator<Integer> comparator = new Comparator<Integer>() { @Override public int compare(Integer o1, Integer o2) { return o1 < o2 ? -1 : (o1 > o2 ? 1 : 0); } }; SearchTree<Integer, Integer> searchTree = new SearchTree<>( comparator); searchTree.add(5, 1); searchTree.add(2, 1); searchTree.add(3, 1); searchTree.add(4, 1); searchTree.printTree(); searchTree.remove(2); System.out.println("\nAfter removing"); searchTree.printTree(); // searchTree.printTree(); } }