updating morri post order

This commit is contained in:
Jidong Xiao
2025-04-25 19:51:36 -04:00
committed by JamesFlare1212
parent efc2fbaaa3
commit 083ae76743
3 changed files with 729 additions and 661 deletions

View File

@@ -3,143 +3,10 @@
<head>
<meta charset="UTF-8">
<title>Morris PostOrder Traversal Animation & Code Display</title>
<style>
html, body { margin: 0; padding: 0; font-family: Arial, sans-serif; }
h1 { text-align: center; margin-top: 10px; margin-bottom: 5px; }
p { text-align: center; margin: 5px 0 15px; }
.visualization-container {
display: flex;
justify-content: space-between;
max-width: 1200px;
margin: 0 auto;
height: 88vh;
}
.code-container {
background-color: #f0f0f0;
border-radius: 10px;
padding: 15px;
width: 48%;
overflow-y: auto;
height: 87vh;
font-size: 15px;
}
pre {
margin: 0;
background-color: #f0f0f0;
overflow-x: auto;
}
code {
font-family: Consolas, "Courier New", monospace;
white-space: pre;
}
.line-number {
color: #666;
display: inline-block;
min-width: 30px;
}
.code-line {
display: block;
width: 100%;
}
.code-line.highlighted {
background-color: #ffeb3b;
}
.tree-container {
background-color: #f0f0f0;
border-radius: 10px;
padding: 15px;
width: 48%;
height: 80vh;
position: relative;
display: flex;
flex-direction: column;
}
#nextStep {
margin: 10px auto;
padding: 8px 15px;
font-size: 16px;
width: fit-content;
cursor: pointer;
background-color: #4CAF50;
color: white;
border: none;
border-radius: 4px;
display: block;
}
#nextStep:hover { background-color: #45a049; }
#nextStep:disabled { background-color: #cccccc; cursor: not-allowed; }
#container { flex-grow: 1; width: 100%; }
.explanation {
margin-top: 10px;
font-size: 14px;
padding: 10px;
background-color: #e8e8e8;
border-radius: 5px;
}
.color-key {
display: flex;
flex-wrap: wrap;
gap: 8px;
margin-bottom: 5px;
padding: 8px;
background-color: #e8e8e8;
border-radius: 5px;
}
.color-item {
display: flex;
align-items: center;
margin-right: 10px;
font-size: 13px;
}
.color-box {
width: 16px;
height: 16px;
border-radius: 3px;
margin-right: 4px;
border: 1px solid #888;
}
.color-arrow {
position: relative;
width: 24px;
height: 3px;
margin-right: 4px;
}
.color-arrow:after {
content: "";
position: absolute;
right: -2px;
top: -4px;
border-left: 6px solid;
border-top: 4px solid transparent;
border-bottom: 4px solid transparent;
}
.dotted-line {
width: 24px;
height: 0;
border-top: 2px dashed #ff5722;
margin-right: 4px;
}
</style>
<link rel="stylesheet" href="style.css">
<!-- Load Konva.js -->
<script src="https://cdn.jsdelivr.net/npm/konva@8.3.13/konva.min.js"></script>
<script src="script.js" defer></script>
</head>
<body>
<h1>Morris Post-Order Traversal Visualization</h1>
@@ -189,531 +56,5 @@
</div>
</div>
</div>
<script>
// Define code content
const codeContent = [
'<span class="line-number">0.</span> <span style="color:blue">void</span> postorderTraversal(<span style="color:blue">TreeNode</span>* root) {',
'<span class="line-number">1.</span> <span style="color:blue">TreeNode</span>* current = root;',
'<span class="line-number">2.</span> <span style="color:blue">TreeNode</span>* rightmost;',
'<span class="line-number">3.</span> <span style="color:blue">while</span> (current != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">4.</span> <span style="color:blue">if</span> (current->left != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">5.</span> rightmost = current->left;',
'<span class="line-number">6.</span> <span style="color:blue">while</span> (rightmost->right != <span style="color:blue">nullptr</span> && rightmost->right != current) {',
'<span class="line-number">7.</span> rightmost = rightmost->right;',
'<span class="line-number">8.</span> }',
'<span class="line-number">9.</span> <span style="color:blue">if</span> (rightmost->right == <span style="color:blue">nullptr</span>) {',
'<span class="line-number">10.</span> rightmost->right = current;',
'<span class="line-number">11.</span> current = current->left;',
'<span class="line-number">12.</span> } <span style="color:blue">else</span> {',
'<span class="line-number">13.</span> rightmost->right = <span style="color:blue">nullptr</span>;',
'<span class="line-number">14.</span> reverseTraverseRightEdge(current->left);',
'<span class="line-number">15.</span> current = current->right;',
'<span class="line-number">16.</span> }',
'<span class="line-number">17.</span> } <span style="color:blue">else</span> {',
'<span class="line-number">18.</span> current = current->right;',
'<span class="line-number">19.</span> }',
'<span class="line-number">20.</span> }',
'<span class="line-number">21.</span> reverseTraverseRightEdge(root); <span style="color:green">// final right edge</span>',
'<span class="line-number">22.</span> <span style="color:blue">return</span>;',
'<span class="line-number">23.</span> }',
'<span class="line-number">24.</span> ',
'<span class="line-number">25.</span> <span style="color:blue">TreeNode</span>* reverse(<span style="color:blue">TreeNode</span>* head) {',
'<span class="line-number">26.</span> <span style="color:blue">TreeNode</span>* prev = <span style="color:blue">nullptr</span>;',
'<span class="line-number">27.</span> <span style="color:blue">TreeNode</span>* next = <span style="color:blue">nullptr</span>;',
'<span class="line-number">28.</span> <span style="color:blue">while</span> (head != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">29.</span> next = head->right;',
'<span class="line-number">30.</span> head->right = prev;',
'<span class="line-number">31.</span> prev = head;',
'<span class="line-number">32.</span> head = next;',
'<span class="line-number">33.</span> }',
'<span class="line-number">34.</span> <span style="color:blue">return</span> prev;',
'<span class="line-number">35.</span> }',
'<span class="line-number">36.</span> ',
'<span class="line-number">37.</span> <span style="color:blue">void</span> reverseTraverseRightEdge(<span style="color:blue">TreeNode</span>* head) {',
'<span class="line-number">38.</span> <span style="color:blue">TreeNode</span>* tail = reverse(head);',
'<span class="line-number">39.</span> <span style="color:blue">TreeNode</span>* current = tail;',
'<span class="line-number">40.</span> <span style="color:blue">while</span> (current != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">41.</span> std::cout << current->val << " ";',
'<span class="line-number">42.</span> current = current->right;',
'<span class="line-number">43.</span> }',
'<span class="line-number">44.</span> reverse(tail); <span style="color:green">// restore structure</span>',
'<span class="line-number">45.</span> }'
];
// Initialize code display with proper structure for highlighting
function initCodeDisplay() {
const codeDisplay = document.getElementById('codeDisplay');
codeContent.forEach((line, index) => {
const lineDiv = document.createElement('div');
lineDiv.className = 'code-line';
lineDiv.setAttribute('data-line', index);
lineDiv.innerHTML = line;
codeDisplay.appendChild(lineDiv);
});
}
// Function to highlight a specific line of code
function highlightLine(lineNum) {
// First, remove all highlights
const codeLines = document.querySelectorAll('.code-line');
codeLines.forEach(line => {
line.classList.remove('highlighted');
});
// Add highlight to the specified line
if (lineNum >= 0 && lineNum < codeContent.length) {
const targetLine = document.querySelector(`.code-line[data-line="${lineNum}"]`);
if (targetLine) {
targetLine.classList.add('highlighted');
// Scroll to make the highlighted line visible
targetLine.scrollIntoView({ behavior: 'smooth', block: 'center' });
}
}
}
// Wait for the "Next Step" button click.
function waitForNext() {
return new Promise(resolve => {
const btn = document.getElementById('nextStep');
btn.disabled = false;
btn.onclick = () => {
btn.disabled = true;
resolve();
};
});
}
// Append text to the output.
function appendOutput(text) {
const out = document.getElementById('output');
out.innerText += text;
}
// Update the explanation text.
function updateExplanation(text) {
document.getElementById('treeExplanation').innerHTML =
'Post-order traversal output: <span id="output">' +
document.getElementById('output').innerText + '</span><br>' + text;
}
// Tree node class using Konva for visualization.
class TreeNode {
constructor(val, x, y) {
this.val = val;
this.left = null;
this.right = null;
this.x = x;
this.y = y;
this.shape = new Konva.Rect({
x: x - 20,
y: y - 20,
width: 40,
height: 40,
fill: 'white',
stroke: '#888',
strokeWidth: 2,
cornerRadius: 4
});
this.label = new Konva.Text({
x: x - 7,
y: y - 10,
text: String(val),
fontSize: 20,
fontFamily: 'Arial',
fill: 'black'
});
this.leftEdge = null;
this.rightEdge = null;
this.threadEdge = null;
this.reversedEdges = [];
}
}
// Initialize Konva stage and layer.
const stage = new Konva.Stage({
container: 'container',
width: document.querySelector('.tree-container').clientWidth - 30,
height: document.querySelector('.tree-container').clientHeight - 140
});
const layer = new Konva.Layer();
stage.add(layer);
// Calculate connection points for arrow drawing.
function calculateConnectionPoints(fromNode, toNode) {
const nodeRadius = 20;
const dx = toNode.x - fromNode.x;
const dy = toNode.y - fromNode.y;
const angle = Math.atan2(dy, dx);
return {
fromX: fromNode.x + nodeRadius * Math.cos(angle),
fromY: fromNode.y + nodeRadius * Math.sin(angle),
toX: toNode.x - nodeRadius * Math.cos(angle),
toY: toNode.y - nodeRadius * Math.sin(angle)
};
}
// Create an arrow between two nodes.
function createArrow(fromNode, toNode, color = '#888', dashed = false) {
const points = calculateConnectionPoints(fromNode, toNode);
const arrow = new Konva.Arrow({
points: [points.fromX, points.fromY, points.toX, points.toY],
pointerLength: 10,
pointerWidth: 8,
fill: color,
stroke: color,
strokeWidth: dashed ? 1 : 2,
dashEnabled: dashed,
dash: dashed ? [5, 5] : null
});
layer.add(arrow);
return arrow;
}
// Draw an edge between two nodes.
function drawEdge(parent, child, isLeft = true) {
const arrow = createArrow(parent, child);
layer.add(arrow);
if (isLeft) { parent.leftEdge = arrow; }
else { parent.rightEdge = arrow; }
arrow.moveToBottom();
return arrow;
}
// Create and remove thread edges.
function createThreadEdge(fromNode, toNode) {
if (fromNode.threadEdge) { fromNode.threadEdge.destroy(); }
const threadArrow = createArrow(fromNode, toNode, '#ff5722', true);
fromNode.threadEdge = threadArrow;
threadArrow.moveToTop();
layer.draw();
return threadArrow;
}
function removeThreadEdge(node) {
if (node && node.threadEdge) {
node.threadEdge.destroy();
node.threadEdge = null;
layer.draw();
}
}
// Highlight and unhighlight a node.
function highlightNode(node, color = '#8bc34a') {
if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
}
function unhighlightNode(node, color = 'white') {
if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
}
// Calculate tree layout.
const stageWidth = stage.width();
const stageHeight = stage.height();
const centerX = stageWidth / 2;
const topY = 40;
const levelHeight = stageHeight / 4;
// Build the 9-node binary tree.
const node1 = new TreeNode(1, centerX, topY);
const node2 = new TreeNode(2, centerX - stageWidth/4, topY + levelHeight);
const node3 = new TreeNode(3, centerX + stageWidth/4, topY + levelHeight);
const node4 = new TreeNode(4, centerX - stageWidth/3, topY + 2*levelHeight);
const node5 = new TreeNode(5, centerX - stageWidth/6, topY + 2*levelHeight);
const node6 = new TreeNode(6, centerX - stageWidth/4, topY + 3*levelHeight);
const node7 = new TreeNode(7, centerX - stageWidth/12, topY + 3*levelHeight);
const node8 = new TreeNode(8, centerX + stageWidth/3, topY + 2*levelHeight);
const node9 = new TreeNode(9, centerX + stageWidth/4, topY + 3*levelHeight);
node1.left = node2;
node1.right = node3;
node2.left = node4;
node2.right = node5;
node5.left = node6;
node5.right = node7;
node3.right = node8;
node8.left = node9;
const nodes = [node1, node2, node3, node4, node5, node6, node7, node8, node9];
nodes.forEach(n => {
layer.add(n.shape);
layer.add(n.label);
});
drawEdge(node1, node2, true);
drawEdge(node1, node3, false);
drawEdge(node2, node4, true);
drawEdge(node2, node5, false);
drawEdge(node5, node6, true);
drawEdge(node5, node7, false);
drawEdge(node3, node8, false);
drawEdge(node8, node9, true);
nodes.forEach(n => {
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
// Visualize the reversal process.
async function visualizeReversal(head) {
const connections = [];
let current = head;
while (current !== null && current.right !== null) {
connections.push({ from: current, to: current.right });
current = current.right;
}
for (const conn of connections) {
if (conn.from.rightEdge) {
conn.from.rightEdge.destroy();
conn.from.rightEdge = null;
}
}
let prev = null;
current = head;
while (current !== null) {
const next = current.right;
if (prev !== null) {
const reversedEdge = createArrow(current, prev, '#e91e63');
current.reversedEdges.push(reversedEdge);
reversedEdge.moveToTop();
}
prev = current;
current = next;
layer.draw();
await waitForNext();
}
return prev;
}
// Restore the original tree structure.
async function visualizeRestore(head) {
nodes.forEach(node => {
if (node.reversedEdges) {
node.reversedEdges.forEach(edge => edge.destroy());
node.reversedEdges = [];
}
});
let current = head;
while (current !== null && current.right !== null) {
if (!current.rightEdge) {
current.rightEdge = createArrow(current, current.right, '#888');
current.rightEdge.moveToBottom();
}
current = current.right;
}
nodes.forEach(n => {
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
}
// Reverse a chain of right pointers.
async function reverseChain(head) {
updateExplanation("Visualizing the reversal of pointers");
await waitForNext();
const reversedHead = await visualizeReversal(head);
let prev = null, curr = head, next;
while (curr !== null) {
next = curr.right;
curr.right = prev;
prev = curr;
curr = next;
}
return prev;
}
// Restore the chain.
async function restoreChain(head) {
updateExplanation("Visualizing the restoration of original pointers");
await waitForNext();
await visualizeRestore(head);
let prev = null, curr = head, next;
while (curr !== null) {
next = curr.right;
curr.right = prev;
prev = curr;
curr = next;
}
return prev;
}
// Reverse traverse the right edge of a subtree.
async function reverseTraverseRightEdge(head) {
if (!head) return;
highlightLine(-1); // Clear code highlighting during reverse traversal
updateExplanation("Executing reverseTraverseRightEdge on node " + head.val);
await waitForNext();
let tail = await reverseChain(head);
layer.draw();
updateExplanation("Visiting nodes along the reversed right edge");
let cur = tail;
while (cur !== null) {
highlightNode(cur, '#4caf50');
layer.draw();
appendOutput(cur.val + " ");
updateExplanation("Visited node: " + cur.val);
await waitForNext();
unhighlightNode(cur, 'white');
layer.draw();
cur = cur.right;
}
updateExplanation("Restoring the original right edge");
await waitForNext();
await restoreChain(tail);
layer.draw();
}
// Morris PostOrder Traversal Animation.
async function postorderTraversal(root) {
// Highlight the initialization steps
highlightLine(0);
updateExplanation("Starting the Morris Post-Order Traversal");
await waitForNext();
highlightLine(1);
updateExplanation("Initializing current = root (node 1)");
await waitForNext();
highlightLine(2);
updateExplanation("Declaring rightmost pointer");
await waitForNext();
let current = root;
while (current !== null) {
highlightLine(3);
updateExplanation("Checking if current is null");
await waitForNext();
highlightNode(current, '#ffeb3b');
layer.draw();
highlightLine(4);
updateExplanation("Checking if current node " + current.val + " has a left child");
await waitForNext();
if (current.left !== null) {
highlightLine(5);
updateExplanation("Current: " + current.val + " has left child, initializing rightmost = current.left (node " + current.left.val + ")");
await waitForNext();
let rightmost = current.left;
highlightNode(rightmost, '#2196f3');
layer.draw();
highlightLine(6);
updateExplanation("Finding the rightmost node in left subtree that doesn't have a thread");
await waitForNext();
while (rightmost.right !== null && rightmost.right !== current) {
highlightLine(7);
updateExplanation("Moving rightmost from " + rightmost.val + " to its right child");
await waitForNext();
unhighlightNode(rightmost, 'white');
rightmost = rightmost.right;
highlightNode(rightmost, '#2196f3');
layer.draw();
highlightLine(6);
updateExplanation("Checking if we've reached the rightmost node or a thread");
await waitForNext();
}
highlightLine(9);
updateExplanation("Checking if rightmost (" + rightmost.val + ") has no thread");
await waitForNext();
if (rightmost.right === null) {
highlightLine(10);
updateExplanation("Creating thread from rightmost (" + rightmost.val + ") to current (" + current.val + ")");
await waitForNext();
createThreadEdge(rightmost, current);
rightmost.right = current;
highlightNode(rightmost, '#03a9f4');
layer.draw();
await waitForNext();
highlightLine(11);
updateExplanation("Moving current to its left child (" + current.left.val + ")");
await waitForNext();
unhighlightNode(rightmost, 'white');
unhighlightNode(current, 'white');
current = current.left;
} else {
highlightLine(13);
updateExplanation("Thread detected from rightmost (" + rightmost.val + ") to current (" + current.val + ") - removing thread");
await waitForNext();
removeThreadEdge(rightmost);
rightmost.right = null;
unhighlightNode(rightmost, 'white');
layer.draw();
highlightLine(14);
updateExplanation("Processing left subtree of current (" + current.val + ")");
await waitForNext();
await reverseTraverseRightEdge(current.left);
highlightLine(15);
updateExplanation("Moving current to its right child");
await waitForNext();
unhighlightNode(current, 'white');
current = current.right;
}
} else {
highlightLine(17);
updateExplanation("Current: " + current.val + " has no left child");
await waitForNext();
highlightLine(18);
updateExplanation("Moving current to its right child");
await waitForNext();
unhighlightNode(current, 'white');
current = current.right;
}
highlightLine(3);
updateExplanation("Checking if current is null");
await waitForNext();
}
highlightLine(21);
updateExplanation("Processing the final right edge starting from root");
await waitForNext();
await reverseTraverseRightEdge(root);
highlightLine(22);
updateExplanation("Morris Post-Order Traversal complete");
await waitForNext();
highlightLine(-1); // Clear highlighting
updateExplanation("Final post-order traversal result: " + document.getElementById('output').innerText);
nodes.forEach(n => {
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
}
window.addEventListener('resize', function() {
stage.width(document.querySelector('.tree-container').clientWidth - 30);
stage.height(document.querySelector('.tree-container').clientHeight - 140);
layer.draw();
});
window.onload = function() {
initCodeDisplay();
document.getElementById('nextStep').disabled = false;
postorderTraversal(node1);
};
</script>
</body>
</html>

View File

@@ -0,0 +1,561 @@
// Define code content
const codeContent = [
'<span class="line-number">0.</span> <span style="color:blue">void</span> postorderTraversal(<span style="color:blue">TreeNode</span>* root) {',
'<span class="line-number">1.</span> <span style="color:blue">TreeNode</span>* current = root;',
'<span class="line-number">2.</span> <span style="color:blue">TreeNode</span>* rightmost;',
'<span class="line-number">3.</span> <span style="color:blue">while</span> (current != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">4.</span> <span style="color:blue">if</span> (current->left != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">5.</span> rightmost = current->left;',
'<span class="line-number">6.</span> <span style="color:blue">while</span> (rightmost->right != <span style="color:blue">nullptr</span> && rightmost->right != current) {',
'<span class="line-number">7.</span> rightmost = rightmost->right;',
'<span class="line-number">8.</span> }',
'<span class="line-number">9.</span> <span style="color:blue">if</span> (rightmost->right == <span style="color:blue">nullptr</span>) {',
'<span class="line-number">10.</span> rightmost->right = current;',
'<span class="line-number">11.</span> current = current->left;',
'<span class="line-number">12.</span> } <span style="color:blue">else</span> {',
'<span class="line-number">13.</span> rightmost->right = <span style="color:blue">nullptr</span>;',
'<span class="line-number">14.</span> reverseTraverseRightEdge(current->left);',
'<span class="line-number">15.</span> current = current->right;',
'<span class="line-number">16.</span> }',
'<span class="line-number">17.</span> } <span style="color:blue">else</span> {',
'<span class="line-number">18.</span> current = current->right;',
'<span class="line-number">19.</span> }',
'<span class="line-number">20.</span> }',
'<span class="line-number">21.</span> reverseTraverseRightEdge(root); <span style="color:green">// final right edge</span>',
'<span class="line-number">22.</span> <span style="color:blue">return</span>;',
'<span class="line-number">23.</span> }',
'<span class="line-number">24.</span> ',
'<span class="line-number">25.</span> <span style="color:blue">TreeNode</span>* reverse(<span style="color:blue">TreeNode</span>* head) {',
'<span class="line-number">26.</span> <span style="color:blue">TreeNode</span>* prev = <span style="color:blue">nullptr</span>;',
'<span class="line-number">27.</span> <span style="color:blue">TreeNode</span>* next = <span style="color:blue">nullptr</span>;',
'<span class="line-number">28.</span> <span style="color:blue">while</span> (head != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">29.</span> next = head->right;',
'<span class="line-number">30.</span> head->right = prev;',
'<span class="line-number">31.</span> prev = head;',
'<span class="line-number">32.</span> head = next;',
'<span class="line-number">33.</span> }',
'<span class="line-number">34.</span> <span style="color:blue">return</span> prev;',
'<span class="line-number">35.</span> }',
'<span class="line-number">36.</span> ',
'<span class="line-number">37.</span> <span style="color:blue">void</span> reverseTraverseRightEdge(<span style="color:blue">TreeNode</span>* head) {',
'<span class="line-number">38.</span> <span style="color:blue">TreeNode</span>* tail = reverse(head);',
'<span class="line-number">39.</span> <span style="color:blue">TreeNode</span>* current = tail;',
'<span class="line-number">40.</span> <span style="color:blue">while</span> (current != <span style="color:blue">nullptr</span>) {',
'<span class="line-number">41.</span> std::cout << current->val << " ";',
'<span class="line-number">42.</span> current = current->right;',
'<span class="line-number">43.</span> }',
'<span class="line-number">44.</span> reverse(tail); <span style="color:green">// restore structure</span>',
'<span class="line-number">45.</span> }'
];
// Initialize code display with proper structure for highlighting
function initCodeDisplay() {
const codeDisplay = document.getElementById('codeDisplay');
codeContent.forEach((line, index) => {
const lineDiv = document.createElement('div');
lineDiv.className = 'code-line';
lineDiv.setAttribute('data-line', index);
lineDiv.innerHTML = line;
codeDisplay.appendChild(lineDiv);
});
}
// Function to highlight a specific line of code
function highlightLine(lineNum) {
// First, remove all highlights
const codeLines = document.querySelectorAll('.code-line');
codeLines.forEach(line => {
line.classList.remove('highlighted');
});
// Add highlight to the specified line
if (lineNum >= 0 && lineNum < codeContent.length) {
const targetLine = document.querySelector(`.code-line[data-line="${lineNum}"]`);
if (targetLine) {
targetLine.classList.add('highlighted');
// Scroll to make the highlighted line visible
targetLine.scrollIntoView({ behavior: 'smooth', block: 'center' });
}
}
}
// Wait for the "Next Step" button click.
function waitForNext() {
return new Promise(resolve => {
const btn = document.getElementById('nextStep');
btn.disabled = false;
btn.onclick = () => {
btn.disabled = true;
resolve();
};
});
}
// Append text to the output.
function appendOutput(text) {
const out = document.getElementById('output');
out.innerText += text;
}
// Update the explanation text.
function updateExplanation(text) {
document.getElementById('treeExplanation').innerHTML =
'Post-order traversal output: <span id="output">' +
document.getElementById('output').innerText + '</span><br>' + text;
}
// Tree node class using Konva for visualization.
class TreeNode {
constructor(val, x, y) {
this.val = val;
this.left = null;
this.right = null;
this.x = x;
this.y = y;
this.shape = new Konva.Rect({
x: x - 20,
y: y - 20,
width: 40,
height: 40,
fill: 'white',
stroke: '#888',
strokeWidth: 2,
cornerRadius: 4
});
this.label = new Konva.Text({
x: x - 7,
y: y - 10,
text: String(val),
fontSize: 20,
fontFamily: 'Arial',
fill: 'black'
});
this.leftEdge = null;
this.rightEdge = null;
this.threadEdge = null;
this.reversedEdges = [];
}
}
// Initialize Konva stage and layer.
const stage = new Konva.Stage({
container: 'container',
width: document.querySelector('.tree-container').clientWidth - 30,
height: document.querySelector('.tree-container').clientHeight - 140
});
const layer = new Konva.Layer();
stage.add(layer);
// Calculate connection points for arrow drawing.
function calculateConnectionPoints(fromNode, toNode) {
const nodeRadius = 20;
const dx = toNode.x - fromNode.x;
const dy = toNode.y - fromNode.y;
const angle = Math.atan2(dy, dx);
return {
fromX: fromNode.x + nodeRadius * Math.cos(angle),
fromY: fromNode.y + nodeRadius * Math.sin(angle),
toX: toNode.x - nodeRadius * Math.cos(angle),
toY: toNode.y - nodeRadius * Math.sin(angle)
};
}
// Create an arrow between two nodes.
function createArrow(fromNode, toNode, color = '#888', dashed = false) {
const points = calculateConnectionPoints(fromNode, toNode);
const arrow = new Konva.Arrow({
points: [points.fromX, points.fromY, points.toX, points.toY],
pointerLength: 10,
pointerWidth: 8,
fill: color,
stroke: color,
strokeWidth: dashed ? 1 : 2,
dashEnabled: dashed,
dash: dashed ? [5, 5] : null
});
layer.add(arrow);
return arrow;
}
// Draw an edge between two nodes.
function drawEdge(parent, child, isLeft = true) {
const arrow = createArrow(parent, child);
layer.add(arrow);
if (isLeft) { parent.leftEdge = arrow; }
else { parent.rightEdge = arrow; }
arrow.moveToBottom();
return arrow;
}
// Create and remove thread edges.
function createThreadEdge(fromNode, toNode) {
if (fromNode.threadEdge) { fromNode.threadEdge.destroy(); }
const threadArrow = createArrow(fromNode, toNode, '#ff5722', true);
fromNode.threadEdge = threadArrow;
threadArrow.moveToTop();
layer.draw();
return threadArrow;
}
function removeThreadEdge(node) {
if (node && node.threadEdge) {
node.threadEdge.destroy();
node.threadEdge = null;
layer.draw();
}
}
// Highlight and unhighlight a node.
function highlightNode(node, color = '#8bc34a') {
if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
}
function unhighlightNode(node, color = 'white') {
if (node && node.shape) { node.shape.to({ fill: color, duration: 0.25 }); }
}
// Calculate tree layout.
const stageWidth = stage.width();
const stageHeight = stage.height();
const centerX = stageWidth / 2;
const topY = 40;
const levelHeight = stageHeight / 4;
// Build the 9-node binary tree.
const node1 = new TreeNode(1, centerX, topY);
const node2 = new TreeNode(2, centerX - stageWidth/4, topY + levelHeight);
const node3 = new TreeNode(3, centerX + stageWidth/4, topY + levelHeight);
const node4 = new TreeNode(4, centerX - stageWidth/3, topY + 2*levelHeight);
const node5 = new TreeNode(5, centerX - stageWidth/6, topY + 2*levelHeight);
const node6 = new TreeNode(6, centerX - stageWidth/4, topY + 3*levelHeight);
const node7 = new TreeNode(7, centerX - stageWidth/12, topY + 3*levelHeight);
const node8 = new TreeNode(8, centerX + stageWidth/3, topY + 2*levelHeight);
const node9 = new TreeNode(9, centerX + stageWidth/4, topY + 3*levelHeight);
node1.left = node2;
node1.right = node3;
node2.left = node4;
node2.right = node5;
node5.left = node6;
node5.right = node7;
node3.right = node8;
node8.left = node9;
const nodes = [node1, node2, node3, node4, node5, node6, node7, node8, node9];
nodes.forEach(n => {
layer.add(n.shape);
layer.add(n.label);
});
drawEdge(node1, node2, true);
drawEdge(node1, node3, false);
drawEdge(node2, node4, true);
drawEdge(node2, node5, false);
drawEdge(node5, node6, true);
drawEdge(node5, node7, false);
drawEdge(node3, node8, false);
drawEdge(node8, node9, true);
nodes.forEach(n => {
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
// Visualize the reversal process.
async function visualizeReversal(head) {
const connections = [];
let current = head;
while (current !== null && current.right !== null) {
connections.push({ from: current, to: current.right });
current = current.right;
}
for (const conn of connections) {
if (conn.from.rightEdge) {
conn.from.rightEdge.destroy();
conn.from.rightEdge = null;
}
}
let prev = null;
current = head;
while (current !== null) {
const next = current.right;
if (prev !== null) {
const reversedEdge = createArrow(current, prev, '#e91e63');
current.reversedEdges.push(reversedEdge);
reversedEdge.moveToTop();
}
prev = current;
current = next;
layer.draw();
await waitForNext();
}
return prev;
}
// Restore the original tree structure.
async function visualizeRestore(head) {
nodes.forEach(node => {
if (node.reversedEdges) {
node.reversedEdges.forEach(edge => edge.destroy());
node.reversedEdges = [];
}
});
let current = head;
while (current !== null && current.right !== null) {
if (!current.rightEdge) {
current.rightEdge = createArrow(current, current.right, '#888');
current.rightEdge.moveToBottom();
}
current = current.right;
}
nodes.forEach(n => {
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
}
// Reverse a chain of right pointers.
async function reverseChain(head) {
updateExplanation("Visualizing the reversal of pointers");
await waitForNext();
const reversedHead = await visualizeReversal(head);
let prev = null, curr = head, next;
while (curr !== null) {
next = curr.right;
curr.right = prev;
prev = curr;
curr = next;
}
return prev;
}
// Restore the chain.
async function restoreChain(head) {
updateExplanation("Visualizing the restoration of original pointers");
await waitForNext();
await visualizeRestore(head);
let prev = null, curr = head, next;
while (curr !== null) {
next = curr.right;
curr.right = prev;
prev = curr;
curr = next;
}
return prev;
}
// Reverse traverse the right edge of a subtree.
async function reverseTraverseRightEdge(head) {
if (!head) return;
highlightLine(-1); // Clear code highlighting during reverse traversal
updateExplanation("Executing reverseTraverseRightEdge on node " + head.val);
await waitForNext();
let tail = await reverseChain(head);
layer.draw();
updateExplanation("Visiting nodes along the reversed right edge");
let cur = tail;
while (cur !== null) {
highlightNode(cur, '#4caf50');
layer.draw();
appendOutput(cur.val + " ");
updateExplanation("Visited node: " + cur.val);
await waitForNext();
unhighlightNode(cur, 'white');
layer.draw();
cur = cur.right;
}
updateExplanation("Restoring the original right edge");
await waitForNext();
await restoreChain(tail);
layer.draw();
}
// Morris PostOrder Traversal Animation.
async function postorderTraversal(root) {
// Ensure all nodes are white at start
nodes.forEach(n => { unhighlightNode(n, 'white'); });
// Highlight the initialization steps
highlightLine(0);
updateExplanation("Starting the Morris Post-Order Traversal");
await waitForNext();
highlightLine(1);
updateExplanation("Initializing current = root (node 1)");
await waitForNext();
highlightLine(2);
updateExplanation("Declaring rightmost pointer");
await waitForNext();
let current = root;
// Main loop
while (current !== null) {
// Clear previous highlighting
nodes.forEach(n => {
if (n !== current) {
unhighlightNode(n, 'white');
}
});
highlightLine(3);
updateExplanation("Checking if current is null");
await waitForNext();
// Always ensure current node is highlighted in yellow
highlightNode(current, '#ffeb3b');
layer.draw();
highlightLine(4);
updateExplanation("Checking if current node " + current.val + " has a left child");
await waitForNext();
if (current.left !== null) {
highlightLine(5);
updateExplanation("Current: " + current.val + " has left child, initializing rightmost = current.left (node " + current.left.val + ")");
await waitForNext();
let rightmost = current.left;
highlightNode(rightmost, '#2196f3');
layer.draw();
highlightLine(6);
updateExplanation("Finding the rightmost node in left subtree that doesn't have a thread");
await waitForNext();
while (rightmost.right !== null && rightmost.right !== current) {
highlightLine(7);
updateExplanation("Moving rightmost from " + rightmost.val + " to its right child");
await waitForNext();
unhighlightNode(rightmost, 'white');
rightmost = rightmost.right;
highlightNode(rightmost, '#2196f3');
// Ensure current is still highlighted
highlightNode(current, '#ffeb3b');
layer.draw();
highlightLine(6);
updateExplanation("Checking if we've reached the rightmost node or a thread");
await waitForNext();
}
highlightLine(9);
updateExplanation("Checking if rightmost (" + rightmost.val + ") has no thread");
await waitForNext();
if (rightmost.right === null) {
highlightLine(10);
updateExplanation("Creating thread from rightmost (" + rightmost.val + ") to current (" + current.val + ")");
await waitForNext();
createThreadEdge(rightmost, current);
rightmost.right = current;
highlightNode(rightmost, '#03a9f4');
// Keep current highlighted
highlightNode(current, '#ffeb3b');
layer.draw();
await waitForNext();
highlightLine(11);
updateExplanation("Moving current to its left child (" + current.left.val + ")");
await waitForNext();
unhighlightNode(rightmost, 'white');
unhighlightNode(current, 'white');
current = current.left;
// Highlight new current
highlightNode(current, '#ffeb3b');
layer.draw();
} else {
highlightLine(13);
updateExplanation("Thread detected from rightmost (" + rightmost.val + ") to current (" + current.val + ") - removing thread");
await waitForNext();
removeThreadEdge(rightmost);
rightmost.right = null;
unhighlightNode(rightmost, 'white');
// Keep current highlighted
highlightNode(current, '#ffeb3b');
layer.draw();
highlightLine(14);
updateExplanation("Processing left subtree of current (" + current.val + ")");
await waitForNext();
// Save current node to restore highlight after recursion
const savedCurrent = current;
await reverseTraverseRightEdge(current.left);
// Restore current node highlight
highlightNode(savedCurrent, '#ffeb3b');
layer.draw();
highlightLine(15);
updateExplanation("Moving current to its right child");
await waitForNext();
unhighlightNode(current, 'white');
current = current.right;
if (current) {
highlightNode(current, '#ffeb3b');
layer.draw();
}
}
} else {
highlightLine(17);
updateExplanation("Current: " + current.val + " has no left child");
await waitForNext();
highlightLine(18);
updateExplanation("Moving current to its right child");
await waitForNext();
unhighlightNode(current, 'white');
current = current.right;
if (current) {
highlightNode(current, '#ffeb3b');
layer.draw();
}
}
highlightLine(3);
updateExplanation("Checking if current is null");
await waitForNext();
}
highlightLine(21);
updateExplanation("Processing the final right edge starting from root");
await waitForNext();
await reverseTraverseRightEdge(root);
highlightLine(22);
updateExplanation("Morris Post-Order Traversal complete");
await waitForNext();
highlightLine(-1); // Clear highlighting
updateExplanation("Final post-order traversal result: " + document.getElementById('output').innerText);
nodes.forEach(n => {
unhighlightNode(n, 'white');
n.shape.moveToTop();
n.label.moveToTop();
});
layer.draw();
}
window.addEventListener('resize', function() {
stage.width(document.querySelector('.tree-container').clientWidth - 30);
stage.height(document.querySelector('.tree-container').clientHeight - 140);
layer.draw();
});
window.onload = function() {
initCodeDisplay();
document.getElementById('nextStep').disabled = false;
postorderTraversal(node1);
};

View File

@@ -0,0 +1,166 @@
html, body {
margin: 0;
padding: 0;
font-family: Arial, sans-serif;
}
h1 {
text-align: center;
margin-top: 10px;
margin-bottom: 5px;
}
p {
text-align: center;
margin: 5px 0 15px;
}
.visualization-container {
display: flex;
justify-content: space-between;
max-width: 1600px; /* Increased from 1200px */
margin: 0 auto;
height: 88vh;
}
.code-container {
background-color: #f0f0f0;
border-radius: 10px;
padding: 15px;
width: 55%; /* Increased from 48% */
overflow-y: auto;
height: 87vh;
font-size: 15px;
}
pre {
margin: 0;
background-color: #f0f0f0;
width: 100%;
}
code {
font-family: Consolas, "Courier New", monospace;
white-space: pre;
display: inline-block;
min-width: 750px; /* Ensure code is wide enough for longest line */
}
#codeDisplay {
width: 100%;
}
.line-number {
color: #666;
display: inline-block;
min-width: 30px;
}
.code-line {
display: block;
width: 100%;
position: relative;
box-sizing: border-box;
}
/* Fix for line highlighting - make sure the entire line is highlighted */
.code-line.highlighted {
background-color: #ffeb3b;
width: 100%;
display: block;
}
.tree-container {
background-color: #f0f0f0;
border-radius: 10px;
padding: 15px;
width: 42%; /* Reduced from 48% to compensate for code container increase */
height: 80vh;
position: relative;
display: flex;
flex-direction: column;
}
#nextStep {
margin: 10px auto;
padding: 8px 15px;
font-size: 16px;
width: fit-content;
cursor: pointer;
background-color: #4CAF50;
color: white;
border: none;
border-radius: 4px;
display: block;
}
#nextStep:hover {
background-color: #45a049;
}
#nextStep:disabled {
background-color: #cccccc;
cursor: not-allowed;
}
#container {
flex-grow: 1;
width: 100%;
}
.explanation {
margin-top: 10px;
font-size: 14px;
padding: 10px;
background-color: #e8e8e8;
border-radius: 5px;
}
.color-key {
display: flex;
flex-wrap: wrap;
gap: 8px;
margin-bottom: 5px;
padding: 8px;
background-color: #e8e8e8;
border-radius: 5px;
}
.color-item {
display: flex;
align-items: center;
margin-right: 10px;
font-size: 13px;
}
.color-box {
width: 16px;
height: 16px;
border-radius: 3px;
margin-right: 4px;
border: 1px solid #888;
}
.color-arrow {
position: relative;
width: 24px;
height: 3px;
margin-right: 4px;
}
.color-arrow:after {
content: "";
position: absolute;
right: -2px;
top: -4px;
border-left: 6px solid;
border-top: 4px solid transparent;
border-bottom: 4px solid transparent;
}
.dotted-line {
width: 24px;
height: 0;
border-top: 2px dashed #ff5722;
margin-right: 4px;
}