java data structure series

Java/data-structure-with-java/data-structure-with-java.iml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4" />

Java/data-structure-with-java/src/main/java/com/javadevjournal/datastructure/tree/BinarySearchTreeTest.java

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+package com.javadevjournal.datastructure.tree;
+
+import com.javadevjournal.datastructure.tree.bst.BinarySearchTree;
+
+public class BinarySearchTreeTest {
+
+    public static void main(String[] args) {
+        BinarySearchTree bst = new BinarySearchTree();
+
+         /* We are building a BST as below
+             52
+           /    \
+          15     56
+         /  \    /  \
+        9    11  54   61
+       / \
+      3   5 */
+
+        bst.insert(52);
+        bst.insert(15);
+        bst.insert(56);
+        bst.insert(9);
+        bst.insert(11);
+        bst.insert(54);
+        bst.insert(3);
+        bst.insert(5);
+        bst.insert(61);
+    }
+}

Java/data-structure-with-java/src/main/java/com/javadevjournal/datastructure/tree/bst/BinarySearchTree.java

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+package com.javadevjournal.datastructure.tree.bst;
+
+
+public class BinarySearchTree {
+
+    private Node root;
+
+    /**
+     * Our main insert method which takes the integer as input and will pass
+     * the parameter to internal insert method with the root node;
+     * @param data
+     * @return boolean status.
+     */
+    public boolean insert(int data) {
+        root = insert(root, data);
+        return true;
+    }
+
+    private Node insert(Node node, int data) {
+
+        /**
+         * If Node is null, either tree is empty or this is the
+         * leaf node and we can create the node and return the new node.
+         */
+        if (node == null) {
+            return new Node(data);
+        }
+
+        /**
+         * if data is less than the current element,
+         * let's go to the left side of the tree. We are giving a recursive call to the insert method
+         * and will wait until response is back.
+         */
+        if (node.data > data) {
+            node.left = insert(node.left, data);
+        }
+
+        /**
+         * If data is greater than the current element,
+         * let's go the right side of the tree.We are giving a recursive call to the insert method
+         * and will wait until response is back. Other option is to use while loop.
+         */
+        if (node.data < data) {
+            node.right = insert(node.right, data);
+        }
+        /**
+         * Element already exist is the tree. Please note there are multiple variations for this step.
+         * Few implementation do not allow duplicate element in BST (we are using same approach).
+         * while other allow duplicate in BST and they can go either to left or right of the tree.
+         */
+        else{
+            return node;
+        }
+        return node;
+    }
+
+    /**
+     * Internal node class representing the node of the BST. This contains the following information
+     * <li>data- actual data stored in the Tree</li>
+     * <li>left - Left child of the node</li>
+     * <li>right - right child of the node</li>
+     */
+    class Node {
+
+        int data;
+        Node left;
+        Node right;
+
+        Node(int data) {
+            this.data = data;
+            //this just for reading.they will be null by default
+            this.left = null;
+            this.right = null;
+        }
+    }
+}