algorithm-neet-code-top-150-python-visual/visual/0572_subtree_of_another_tree.html at main · kimtth/algorithm-neet-code-top-150-python-visual · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Subtree of Another Tree - LeetCode 572</title>
    <link rel="stylesheet" href="styles.css">
    <script src="https://d3js.org/d3.v7.min.js"></script>
</head>
<body>
    <div class="container">
        <div class="problem-info">
            <h1><span class="problem-number">#0572</span> Subtree of Another Tree</h1>
            <p><strong>Problem:</strong> Check if a tree is a subtree of another tree. A subtree includes the node and all its descendants.</p>
            <p><strong>Pattern:</strong> DFS + Tree Comparison - For each node, check if it matches the subtree</p>
            <div class="problem-meta">
                <span class="meta-tag">🌳 Tree</span>
                <span class="meta-tag">⏱️ O(n)</span>
            </div>
            <div class="file-ref">
                📄 Python: <code>python/0572_subtree_of_another_tree/0572_subtree_of_another_tree.py</code>
            </div>

        </div>

        <div class="explanation-panel">
            <h4>🧠 How It Works (Layman's Terms)</h4>
            <p>Tree traversal is like <strong>exploring a family tree</strong>:</p>
            <ul>
                <li><strong>Root:</strong> Start at the top node</li>
                <li><strong>Recurse:</strong> Visit left and right children</li>
                <li><strong>Base case:</strong> Stop at null/leaf nodes</li>
                <li><strong>Combine:</strong> Build answer from subtree results</li>
            </ul>
        </div>


        <div class="visualization-section">
            <h3>🎬 Step-by-Step Visualization</h3>

            <div class="visualization">
            <svg id="mainSvg"></svg>
        </div>

        <div class="controls">
            <button id="stepBtn">Step</button>
            <button id="autoBtn">Auto Run</button>
            <button id="resetBtn">Reset</button>
            <div class="speed-control">
                <label for="speed">Speed:</label>
                <input type="range" id="speed" min="100" max="2000" value="800">
            </div>
        </div>

        <div class="status" id="status">Click "Step" to check if subRoot is a subtree</div>

        <div class="variables">
            <div class="var-item">
                <span class="var-label">Main Tree Node:</span>
                <span id="mainNodeDisplay">-</span>
            </div>
            <div class="var-item">
                <span class="var-label">Comparing:</span>
                <span id="compareDisplay">-</span>
            </div>
            <div class="var-item">
                <span class="var-label">Result:</span>
                <span id="resultDisplay">-</span>
            </div>
        </div>

        </div>

        <div class="code-section">
            <h3>💻 Python Solution</h3>
            <div class="code-block">
                <pre><span class="keyword">def</span> <span class="function">isSubtree</span>(root, subRoot):
    <span class="string">"""
    DFS checking each node as potential subtree root.
    Time: O(m*n), Space: O(h)
    """</span>
    <span class="keyword">def</span> <span class="function">isSameTree</span>(p, q):
        <span class="keyword">if</span> <span class="keyword">not</span> p <span class="keyword">and</span> <span class="keyword">not</span> q:
            <span class="keyword">return</span> <span class="keyword">True</span>
        <span class="keyword">if</span> <span class="keyword">not</span> p <span class="keyword">or</span> <span class="keyword">not</span> q:
            <span class="keyword">return</span> <span class="keyword">False</span>
        <span class="keyword">return</span> (p.val == q.val <span class="keyword">and</span>
                <span class="function">isSameTree</span>(p.left, q.left) <span class="keyword">and</span>
                <span class="function">isSameTree</span>(p.right, q.right))

    <span class="keyword">if</span> <span class="keyword">not</span> root:
        <span class="keyword">return</span> <span class="keyword">False</span>
    <span class="keyword">if</span> <span class="function">isSameTree</span>(root, subRoot):
        <span class="keyword">return</span> <span class="keyword">True</span>
    <span class="keyword">return</span> (<span class="function">isSubtree</span>(root.left, subRoot) <span class="keyword">or</span>
            <span class="function">isSubtree</span>(root.right, subRoot))</pre>
            </div>
        </div>
    </div>

    <script>
        // Main tree
        const mainTree = {
            val: 3,
            left: {
                val: 4,
                left: {val: 1, left: null, right: null},
                right: {val: 2, left: null, right: null}
            },
            right: {val: 5, left: null, right: null}
        };

        // Subtree to find
        const subTree = {
            val: 4,
            left: {val: 1, left: null, right: null},
            right: {val: 2, left: null, right: null}
        };

        let nodeStates = {}; // path -> 'checking' | 'match' | 'nomatch' | 'found'
        let compareStates = {}; // 'sub_path' -> 'comparing' | 'match' | 'nomatch'
        let callStack = [{type: 'main', node: mainTree, path: 'root'}];
        let foundSubtree = false;
        let currentCompare = null;
        let autoRunning = false;
        let autoTimer = null;

        const width = 800;
        const height = 400;
        const svg = d3.select("#mainSvg")
            .attr("width", width)
            .attr("height", height);

        function drawTree(node, x, y, level, path, isSubtree, statesMap) {
            if (!node) return;

            const nodeRadius = 22;
            const dx = isSubtree ? 45 / (level + 1) : 80 / (level + 1);
            const dy = isSubtree ? 50 : 60;

            // Edges
            if (node.left) {
                svg.append("line")
                    .attr("x1", x).attr("y1", y + nodeRadius)
                    .attr("x2", x - dx).attr("y2", y + dy - nodeRadius)
                    .attr("stroke", "#ddd").attr("stroke-width", 2);
                drawTree(node.left, x - dx, y + dy, level + 1, path + 'L', isSubtree, statesMap);
            }
            if (node.right) {
                svg.append("line")
                    .attr("x1", x).attr("y1", y + nodeRadius)
                    .attr("x2", x + dx).attr("y2", y + dy - nodeRadius)
                    .attr("stroke", "#ddd").attr("stroke-width", 2);
                drawTree(node.right, x + dx, y + dy, level + 1, path + 'R', isSubtree, statesMap);
            }

            // Node
            const state = statesMap[path];

            let fill = "#e3f2fd", stroke = "#1976d2";
            if (state === 'checking' || state === 'comparing') {
                fill = "#ffeb3b"; stroke = "#f57c00";
            } else if (state === 'match') {
                fill = "#c8e6c9"; stroke = "#4caf50";
            } else if (state === 'nomatch') {
                fill = "#ffcdd2"; stroke = "#e53935";
            } else if (state === 'found') {
                fill = "#b39ddb"; stroke = "#673ab7";
            }

            svg.append("circle")
                .attr("cx", x).attr("cy", y).attr("r", nodeRadius)
                .attr("fill", fill).attr("stroke", stroke).attr("stroke-width", 2);

            svg.append("text")
                .attr("x", x).attr("y", y + 5)
                .attr("text-anchor", "middle")
                .attr("font-size", isSubtree ? "14px" : "16px")
                .attr("font-weight", "bold")
                .text(node.val);
        }

        function draw() {
            svg.selectAll("*").remove();

            // Main tree label
            svg.append("text")
                .attr("x", 200).attr("y", 25)
                .attr("text-anchor", "middle")
                .attr("font-weight", "bold")
                .text("Main Tree (root)");

            // Subtree label
            svg.append("text")
                .attr("x", 620).attr("y", 25)
                .attr("text-anchor", "middle")
                .attr("font-weight", "bold")
                .text("SubRoot");

            // Draw main tree
            drawTree(mainTree, 200, 80, 0, 'root', false, nodeStates);

            // Draw subtree
            drawTree(subTree, 620, 80, 0, 'sub', true, compareStates);

            // Divider
            svg.append("line")
                .attr("x1", 430).attr("y1", 40)
                .attr("x2", 430).attr("y2", height - 40)
                .attr("stroke", "#ddd").attr("stroke-width", 2)
                .attr("stroke-dasharray", "5,5");

            // Legend
            const legend = [
                {color: "#e3f2fd", label: "Not checked"},
                {color: "#ffeb3b", label: "Checking"},
                {color: "#c8e6c9", label: "Match"},
                {color: "#ffcdd2", label: "No match"},
                {color: "#b39ddb", label: "Subtree found"}
            ];

            legend.forEach((item, i) => {
                svg.append("rect")
                    .attr("x", 10 + i * 110).attr("y", height - 30)
                    .attr("width", 15).attr("height", 15)
                    .attr("fill", item.color)
                    .attr("stroke", "#999");
                svg.append("text")
                    .attr("x", 30 + i * 110).attr("y", height - 18)
                    .attr("font-size", "10px")
                    .text(item.label);
            });

            // Result
            if (foundSubtree) {
                svg.append("rect")
                    .attr("x", width / 2 - 80).attr("y", height - 70)
                    .attr("width", 160).attr("height", 35)
                    .attr("rx", 8)
                    .attr("fill", "#c8e6c9").attr("stroke", "#4caf50");

                svg.append("text")
                    .attr("x", width / 2).attr("y", height - 46)
                    .attr("text-anchor", "middle")
                    .attr("font-size", "16px")
                    .attr("font-weight", "bold")
                    .text("✓ Subtree Found!");
            }
        }

        function getNode(tree, path) {
            let node = tree;
            for (let c of path.slice(4)) { // skip 'root' or 'sub_'
                if (!node) return null;
                node = c === 'L' ? node.left : node.right;
            }
            return node;
        }

        function step() {
            if (foundSubtree || callStack.length === 0) {
                if (!foundSubtree && callStack.length === 0) {
                    document.getElementById("status").textContent = "Subtree NOT found!";
                    document.getElementById("resultDisplay").textContent = "Not Found";
                }
                draw();
                return false;
            }

            const task = callStack.pop();

            if (task.type === 'main') {
                // Check this main tree node as potential subtree root
                const {node, path} = task;
                if (!node) return callStack.length > 0;

                nodeStates[path] = 'checking';
                document.getElementById("mainNodeDisplay").textContent = `Node ${node.val}`;

                // Start comparison with subtree
                callStack.push({type: 'main_done', path});
                callStack.push({type: 'compare', mainPath: path, subPath: 'sub', mainNode: node, subNode: subTree});

                document.getElementById("status").textContent =
                    `Checking if subtree rooted at ${node.val} matches subRoot...`;
            } else if (task.type === 'compare') {
                const {mainPath, subPath, mainNode, subNode} = task;

                // Both null = match
                if (!mainNode && !subNode) {
                    compareStates[subPath] = 'match';
                    return callStack.length > 0;
                }

                // One null = no match
                if (!mainNode || !subNode) {
                    compareStates[subPath] = 'nomatch';
                    return callStack.length > 0;
                }

                compareStates[subPath] = 'comparing';
                document.getElementById("compareDisplay").textContent =
                    `Main(${mainNode.val}) vs Sub(${subNode.val})`;

                if (mainNode.val !== subNode.val) {
                    compareStates[subPath] = 'nomatch';
                    document.getElementById("status").textContent =
                        `${mainNode.val} ≠ ${subNode.val} - no match`;
                } else {
                    // Values match, check children
                    callStack.push({type: 'compare_done', subPath});
                    callStack.push({
                        type: 'compare',
                        mainPath: mainPath + 'R',
                        subPath: subPath + 'R',
                        mainNode: mainNode.right,
                        subNode: subNode.right
                    });
                    callStack.push({
                        type: 'compare',
                        mainPath: mainPath + 'L',
                        subPath: subPath + 'L',
                        mainNode: mainNode.left,
                        subNode: subNode.left
                    });
                    document.getElementById("status").textContent =
                        `${mainNode.val} = ${subNode.val} ✓ - checking children...`;
                }
            } else if (task.type === 'compare_done') {
                const {subPath} = task;
                const leftMatch = compareStates[subPath + 'L'] === 'match' ||
                                  !getNode(subTree, subPath.slice(3) + 'L');
                const rightMatch = compareStates[subPath + 'R'] === 'match' ||
                                   !getNode(subTree, subPath.slice(3) + 'R');

                if (leftMatch && rightMatch) {
                    compareStates[subPath] = 'match';
                } else {
                    compareStates[subPath] = 'nomatch';
                }
            } else if (task.type === 'main_done') {
                const {path} = task;
                const matched = compareStates['sub'] === 'match';

                if (matched) {
                    nodeStates[path] = 'found';
                    foundSubtree = true;
                    document.getElementById("status").textContent =
                        `Found subtree at node ${getNode(mainTree, path).val}!`;
                    document.getElementById("resultDisplay").textContent = "Found!";
                } else {
                    nodeStates[path] = 'nomatch';
                    // Reset compare states and try children
                    compareStates = {};
                    const node = getNode(mainTree, path);
                    if (node) {
                        if (node.right) {
                            callStack.push({type: 'main', node: node.right, path: path + 'R'});
                        }
                        if (node.left) {
                            callStack.push({type: 'main', node: node.left, path: path + 'L'});
                        }
                    }
                    document.getElementById("status").textContent =
                        `No match at ${node?.val}, trying other nodes...`;
                }
            }

            draw();
            return callStack.length > 0 && !foundSubtree;
        }

        function reset() {
            nodeStates = {};
            compareStates = {};
            callStack = [{type: 'main', node: mainTree, path: 'root'}];
            foundSubtree = false;
            autoRunning = false;
            if (autoTimer) clearInterval(autoTimer);

            document.getElementById("mainNodeDisplay").textContent = "-";
            document.getElementById("compareDisplay").textContent = "-";
            document.getElementById("resultDisplay").textContent = "-";
            document.getElementById("status").textContent =
                'Click "Step" to check if subRoot is a subtree';
            document.getElementById("autoBtn").textContent = "Auto Run";

            draw();
        }

        function autoRun() {
            if (autoRunning) {
                autoRunning = false;
                clearInterval(autoTimer);
                document.getElementById("autoBtn").textContent = "Auto Run";
            } else {
                autoRunning = true;
                document.getElementById("autoBtn").textContent = "Pause";
                const speed = 2100 - document.getElementById("speed").value;
                autoTimer = setInterval(() => {
                    if (!step()) {
                        autoRunning = false;
                        clearInterval(autoTimer);
                        document.getElementById("autoBtn").textContent = "Auto Run";
                    }
                }, speed);
            }
        }

        document.getElementById("stepBtn").addEventListener("click", step);
        document.getElementById("autoBtn").addEventListener("click", autoRun);
        document.getElementById("resetBtn").addEventListener("click", reset);

        draw();
    </script>
</body>
</html>