diff --git a/src/Traversal.java b/src/Traversal.java index 8da0f79..933bcc8 100644 --- a/src/Traversal.java +++ b/src/Traversal.java @@ -1,5 +1,154 @@ +import java.util.HashMap; +import java.util.LinkedList; +import java.util.Map; +import java.util.Queue; +import java.util.Stack; + public class Traversal { public static void main(String[] args) { + TreeNode root = new TreeNode(10, null, null); + root.left = new TreeNode(9, null, null); + root.left.left = new TreeNode(5, null, null); + root.left.right = new TreeNode(2, null, null); + + root.right = new TreeNode(15, null, null); + root.right.left = new TreeNode(-3, null, null); + root.right.right = new TreeNode(5, null, null); + root.right.right.right = new TreeNode(22, null, null); + + TreeNode stringRoot = new TreeNode("hello", null, null); + stringRoot.left = new TreeNode("bine", null, null); + stringRoot.left.left = new TreeNode("hello", null, null); + stringRoot.left.right = new TreeNode("lime", null, null); + + stringRoot.right = new TreeNode("chime", null, null); + stringRoot.right.left = new TreeNode("lime", null, null); + stringRoot.right.right = new TreeNode("climb", null, null); + stringRoot.right.right.right = new TreeNode("help", null, null); + System.out.println(); + + // System.out.print("pre-order: "); + // preOrder(root); + // System.out.println(); + // System.out.print("post-order: "); + // postOrder(root); + // System.out.println(); + // System.out.print("in-order: "); + // inOrder(root); + + // inOrder(stringRoot); + // printGreater(root, 4); + // System.out.println(countNodes(stringRoot)); + + TreeNode megaRoot = new TreeNode(1, null, null); + TreeNode current = megaRoot; + + for(int i = 2; i <= 5000; i++){ + current.right = new TreeNode(i, null, null); + current = current.right; + + } + // preOrder(megaRoot); + // System.out.println(toMap(stringRoot)); + // System.out.println("Preorder recursive"); + // preOrder(root); + // System.out.println("Preorder recursive"); + // preOrderIter(megaRoot); + LevelOrder(root); + } + + //Print a tree rooted at a given node in pre-order + public static void preOrder(TreeNode node){ + if (node == null) return; + System.out.print(node.value + " "); + preOrder(node.left); + preOrder(node.right); + } + + public static void preOrderIter(TreeNode node) { + Stack> stack = new Stack<>(); + + stack.push(node); + + while(!stack.empty()){ + TreeNode current = stack.pop(); + + if(current == null){ + continue; + } + + System.out.println(current.value); + stack.push(current.right); + stack.push(current.left); + + + } + } + + public static void LevelOrder(TreeNode node) { + Queue> queue = new LinkedList<>(); + + queue.add(node); + + while(!queue.isEmpty()){ + TreeNode current = queue.poll(); + + if(current == null){ + continue; + } + + System.out.println(current.value); + + queue.add(current.left); + queue.add(current.right); + + + } + } + public static Map toMap(TreeNode node){ + Map counts = new HashMap<>(); + toMap(node, counts); + return counts; + } + + private static void toMap(TreeNode node, Map counts){ + if(node == null) { return;} + // fill up those counts + counts.put(node.value, counts.getOrDefault(node.value, 0) + 1); + toMap(node.left, counts); + toMap(node.right, counts); + } + + + public static int countNodes(TreeNode node){ + return node == null ? 0 : 1 + countNodes(node.left) + countNodes(node.right); + // if (node == null) { return 0; } + // int leftCount = countNodes(node.left); + // int rightCount = countNodes(node.right); + // int overallCount = leftCount + rightCount + 1; + // return overallCount; + } + public static void printGreater(TreeNode node, int threshold){ + if(node == null) return; + if (node.value > threshold) { System.out.println(node.value); } + printGreater(node.left, threshold); + printGreater(node.right, threshold); + } + + + //Print a tree rooted at a given node in pre-order + public static void postOrder(TreeNode node){ + if (node == null) return; + postOrder(node.left); + postOrder(node.right); + System.out.print(node.value + " "); + } + //Print a tree rooted at a given node in pre-order + public static void inOrder(TreeNode node){ + if (node == null) return; + postOrder(node.left); + System.out.print(node.value + " "); + postOrder(node.right); } } diff --git a/src/TreeNode.java b/src/TreeNode.java index acd9639..19d9315 100644 --- a/src/TreeNode.java +++ b/src/TreeNode.java @@ -1,4 +1,12 @@ -public class TreeNode { +public class TreeNode { + public T value; + public TreeNode left; + public TreeNode right; + public TreeNode(T value, TreeNode left, TreeNode right){ + this.value = value; + this.left = left; + this.right = right; + } } \ No newline at end of file