WIP BST Kth Element

Author: triplel

Diff for: src/main/java/com/liangsworld/bst/BSTFunctions.java

@@ -0,0 +1,65 @@
+package com.liangsworld.bst;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: liliang
+ * Date: 12/19/14
+ * Time: 11:31 AM
+ * To change this template use File | Settings | File Templates.
+ */
+public class BSTFunctions {
+
+
+	int counter = 0;
+
+	public void resetCounter(){
+		counter = 0;
+	}
+
+	private BSTNode targetNode = null;
+
+	public void resetTargetNode(){
+		targetNode = null;
+	}
+
+	//print kth smallest
+	void printKthSmallest(BSTNode node, int k){
+		if (node == null)
+			return;
+
+		printKthSmallest(node.getLeft(), k);
+
+		if(++ counter == k)
+			System.out.println(String.format("%d -th smallest is %d", k, node.getValue()));
+
+		printKthSmallest(node.getRight(), k);
+	}
+
+	//print kth smallest
+	BSTNode getKthSmallest(BSTNode node, int k){
+		if (node == null)
+			return null;
+		else{
+			getKthSmallest(node.getLeft(), k);
+
+//			if(targetNode == null && ++counter == k)
+			if(++counter == k)
+				return node;
+
+//			return getKthSmallest(node.getRight(), k);
+			return getKthSmallest(node.getRight(), k);
+		}
+//
+//		if(++ counter == k)
+//			targetNode = node ;
+//
+//		getKthSmallest(node.getRight(), k);
+//
+//		return targetNode;
+	}
+
+
+	//print kth largest
+
+
+}

Diff for: src/main/java/com/liangsworld/bst/BSTNode.java

@@ -0,0 +1,51 @@
+package com.liangsworld.bst;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: liliang
+ * Date: 12/19/14
+ * Time: 11:32 AM
+ * To change this template use File | Settings | File Templates.
+ */
+public class BSTNode {
+
+	int value;
+	BSTNode left, right;
+
+	public BSTNode(int value){
+		this.value = value;
+	}
+
+	public BSTNode(int value, BSTNode left, BSTNode right) {
+		this.value = value;
+		this.left = left;
+		this.right = right;
+	}
+
+	public int getValue() {
+		return value;
+	}
+
+	public void setValue(int value) {
+		this.value = value;
+	}
+
+	public BSTNode getLeft() {
+		return left;
+	}
+
+	public void setLeft(BSTNode left) {
+		this.left = left;
+	}
+
+	public BSTNode getRight() {
+		return right;
+	}
+
+	public void setRight(BSTNode right) {
+		this.right = right;
+	}
+
+
+
+}

Diff for: src/test/java/com/liangsworld/bst/TestKthNode.java

@@ -0,0 +1,88 @@
+package com.liangsworld.bst;
+
+import junit.framework.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.Random;
+
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Created with IntelliJ IDEA.
+ * User: liliang
+ * Date: 12/19/14
+ * Time: 11:42 AM
+ * To change this template use File | Settings | File Templates.
+ */
+public class TestKthNode {
+
+	BSTNode root;
+	BSTFunctions functions;
+
+	@Before
+	public void setUp(){
+		constructBST();
+		functions = new BSTFunctions();
+	}
+
+	@Test
+	public void testPrintKthSmallest(){
+		functions.printKthSmallest(root,1);
+		functions.resetCounter();
+		functions.printKthSmallest(root,3);
+		functions.resetCounter();
+		functions.printKthSmallest(root,6);
+		functions.resetCounter();
+	}
+
+	@Test
+	public void testGetKthSmallest(){
+//		Assert.assertEquals(functions.getKthSmallest(root,1).getValue(), 2);
+//		functions.resetTargetNode();
+		Assert.assertEquals(functions.getKthSmallest(root,3).getValue(), 18);
+		functions.resetTargetNode();
+//		Assert.assertEquals(functions.getKthSmallest(root,6).getValue(), 48);
+//		functions.resetTargetNode();
+//		Assert.assertEquals(functions.getKthSmallest(root,8).getValue(), 65);
+//		functions.resetTargetNode();
+//		Assert.assertEquals(functions.getKthSmallest(root,13).getValue(), 123);
+//		functions.resetTargetNode();
+	}
+
+	private void constructBST(){
+		BSTNode node1 = new BSTNode(2);
+		BSTNode node2 = new BSTNode(18);
+		BSTNode node3 = new BSTNode(12);
+		BSTNode node4 = new BSTNode(38);
+		BSTNode node5 = new BSTNode(43);
+		BSTNode node6 = new BSTNode(48);
+		BSTNode node7 = new BSTNode(52);
+		BSTNode node8 = new BSTNode(83);
+		BSTNode node9 = new BSTNode(71);
+		BSTNode node10 = new BSTNode(65);
+		BSTNode node11 = new BSTNode(79);
+		BSTNode node12 = new BSTNode(152);
+		BSTNode node13 = new BSTNode(99);
+		BSTNode node14 = new BSTNode(123);
+		BSTNode node15 = new BSTNode(291);
+
+		node3.setLeft(node1);
+		node3.setRight(node2);
+		node4.setLeft(node3);
+		node4.setRight(node5);
+		node5.setRight(node6);
+		node7.setLeft(node4);
+		node7.setRight(node8);
+		node8.setLeft(node9);
+		node8.setRight(node12);
+		node9.setLeft(node10);
+		node9.setRight(node11);
+		node12.setLeft(node13);
+		node12.setRight(node15);
+		node13.setRight(node14);
+
+		root = node7;
+	}
+}