algorithm-neet-code-top-150-python-visual/visual/0953_verifying_an_alien_dictionary.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>Verifying an Alien Dictionary - LeetCode 953</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">#953</span> Verifying an Alien Dictionary</h1>
            <p>In an alien language, the alphabet order is different. Given a list of words and the alien alphabet order, check if the words are sorted lexicographically in this alien language.</p>
            <div class="problem-meta">
                <span class="meta-tag">📁 Array & Hashing</span>
                <span class="meta-tag">🔤 String</span>
                <span class="meta-tag">⏱️ O(n × m)</span>
            </div>
            <div class="file-ref">
                📄 Python: <a href="../python/0953_verifying_an_alien_dictionary/0953_verifying_an_alien_dictionary.py">0953_verifying_an_alien_dictionary.py</a>
            </div>
            </div>

        <div class="explanation-panel">
            <h4>💡 How It Works (Layman's Terms)</h4>
            <ul>
                <li><strong>Alien Alphabet:</strong> Instead of a-b-c-d..., aliens might use h-l-a-b... as their order</li>
                <li><strong>Lexicographic Order:</strong> Like dictionary order, but using the alien alphabet</li>
                <li><strong>Comparison:</strong> Compare adjacent words character by character</li>
                <li><strong>Rule 1:</strong> If first different character in word1 comes AFTER word2's in alien order → NOT sorted</li>
                <li><strong>Rule 2:</strong> If word1 is longer but word2 is a prefix of word1 (like "apple" vs "app") → NOT sorted</li>
            </ul>
        </div>


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

            <div class="controls">
                <button class="btn btn-primary" id="stepBtn" onclick="step()">Step</button>
                <button class="btn btn-success" id="autoBtn" onclick="toggleAuto()">Auto Run</button>
                <button class="btn btn-warning" onclick="reset()">Reset</button>
            </div>

            <div class="status-message" id="statusMessage">
                Click "Step" or "Auto Run" to check if words are sorted in alien order
            </div>

            <div class="array-section">
                <div class="array-label">Alien Alphabet Order:</div>
                <div class="array-container" id="alphabetContainer" style="gap: 4px;"></div>
            </div>

            <div class="array-section">
                <div class="array-label">Words to Check:</div>
                <div class="array-container" id="wordsContainer"></div>
            </div>

            <div class="array-section">
                <div class="array-label">Character Comparison:</div>
                <div id="comparisonContainer" style="font-size: 1.3em; padding: 20px; background: #f5f5f5; border-radius: 10px;"></div>
            </div>

            <div class="info-box" id="resultBox" style="display: none;"></div>
        </div>

        <div class="code-section">
            <h3>💻 Python Solution</h3>
            <div class="code-block">
                <pre><span class="keyword">def</span> <span class="function">isAlienSorted</span>(self, words: List[<span class="class-name">str</span>], order: <span class="class-name">str</span>) -> <span class="class-name">bool</span>:
    <span class="comment"># Create order map: char -> position</span>
    order_map = {char: i <span class="keyword">for</span> i, char <span class="keyword">in</span> <span class="function">enumerate</span>(order)}

    <span class="keyword">for</span> i <span class="keyword">in</span> <span class="function">range</span>(<span class="function">len</span>(words) - <span class="number">1</span>):
        word1, word2 = words[i], words[i + <span class="number">1</span>]
        <span class="keyword">for</span> j <span class="keyword">in</span> <span class="function">range</span>(<span class="function">len</span>(word1)):
            <span class="keyword">if</span> j >= <span class="function">len</span>(word2):  <span class="comment"># word2 is prefix of word1</span>
                <span class="keyword">return</span> <span class="class-name">False</span>
            <span class="keyword">if</span> word1[j] != word2[j]:
                <span class="keyword">if</span> order_map[word2[j]] < order_map[word1[j]]:
                    <span class="keyword">return</span> <span class="class-name">False</span>
                <span class="keyword">break</span>
    <span class="keyword">return</span> <span class="class-name">True</span></pre>
            </div>
        </div>
    </div>

    <script>
        const alienOrder = "hlabcdefgijkmnopqrstuvwxyz";
        const words = ["hello", "leetcode"];
        const orderMap = {};
        alienOrder.split('').forEach((c, i) => orderMap[c] = i);

        let currentPair = 0;
        let charIndex = 0;
        let phase = 'init';
        let autoInterval = null;

        function init() {
            renderAlphabet();
            renderWords();
            document.getElementById('comparisonContainer').innerHTML = 'Comparison will appear here...';
            document.getElementById('resultBox').style.display = 'none';
        }

        function renderAlphabet() {
            const container = document.getElementById('alphabetContainer');
            container.innerHTML = '';
            alienOrder.split('').forEach((char, idx) => {
                const box = document.createElement('div');
                box.className = 'array-box small';
                box.id = `alpha-${char}`;
                box.style.width = '35px';
                box.style.height = '35px';
                box.style.fontSize = '1em';
                box.innerHTML = `${char}<span class="index-label">${idx}</span>`;
                container.appendChild(box);
            });
        }

        function renderWords() {
            const container = document.getElementById('wordsContainer');
            container.innerHTML = '';
            words.forEach((word, idx) => {
                const box = document.createElement('div');
                box.className = 'array-box';
                box.id = `word-${idx}`;
                box.style.width = 'auto';
                box.style.minWidth = '100px';
                box.style.padding = '10px 20px';
                box.innerHTML = `"${word}"<span class="index-label">[${idx}]</span>`;
                container.appendChild(box);
            });
        }

        function highlightChar(char) {
            document.querySelectorAll('[id^="alpha-"]').forEach(b => b.classList.remove('highlight'));
            if (char && document.getElementById(`alpha-${char}`)) {
                document.getElementById(`alpha-${char}`).classList.add('highlight');
            }
        }

        function step() {
            if (phase === 'init') {
                phase = 'comparing';
                currentPair = 0;
                charIndex = 0;
                document.getElementById('statusMessage').textContent =
                    `Comparing adjacent pairs: "${words[0]}" vs "${words[1]}"`;
                document.getElementById(`word-0`).classList.add('current');
                document.getElementById(`word-1`).classList.add('current');
            } else if (phase === 'comparing') {
                if (currentPair >= words.length - 1) {
                    phase = 'done';
                    document.getElementById('resultBox').style.display = 'block';
                    document.getElementById('resultBox').className = 'info-box secondary';
                    document.getElementById('resultBox').textContent = '✅ All pairs are in correct order! Words are SORTED.';
                    document.getElementById('statusMessage').textContent = 'Verification complete!';
                    document.getElementById('stepBtn').disabled = true;
                    stopAuto();
                    return;
                }

                const word1 = words[currentPair];
                const word2 = words[currentPair + 1];

                if (charIndex >= word1.length) {
                    // word1 is done, it's valid (word1 <= word2 in length or found difference)
                    document.getElementById('comparisonContainer').innerHTML =
                        `✓ "${word1}" ≤ "${word2}" — All characters matched and word1 ended first or is equal prefix`;
                    currentPair++;
                    charIndex = 0;
                    document.querySelectorAll('[id^="word-"]').forEach(b => b.classList.remove('current'));
                    if (currentPair < words.length - 1) {
                        document.getElementById(`word-${currentPair}`).classList.add('current');
                        document.getElementById(`word-${currentPair + 1}`).classList.add('current');
                    }
                    document.getElementById('statusMessage').textContent =
                        currentPair < words.length - 1 ?
                        `Moving to next pair: "${words[currentPair]}" vs "${words[currentPair + 1]}"` :
                        'All pairs checked!';
                    return;
                }

                if (charIndex >= word2.length) {
                    // word2 is shorter but word1 still has chars → NOT sorted
                    phase = 'done';
                    document.getElementById('comparisonContainer').innerHTML =
                        `❌ "${word1}" > "${word2}" — word2 is a prefix of word1!`;
                    document.getElementById('resultBox').style.display = 'block';
                    document.getElementById('resultBox').className = 'info-box highlight';
                    document.getElementById('resultBox').textContent = '❌ NOT SORTED! word2 is prefix of word1.';
                    document.getElementById('stepBtn').disabled = true;
                    stopAuto();
                    return;
                }

                const c1 = word1[charIndex];
                const c2 = word2[charIndex];
                const pos1 = orderMap[c1];
                const pos2 = orderMap[c2];

                highlightChar(c1);

                if (c1 === c2) {
                    document.getElementById('comparisonContainer').innerHTML =
                        `Comparing char[${charIndex}]: '${c1}' (pos ${pos1}) = '${c2}' (pos ${pos2}) → Same, continue...`;
                    document.getElementById('statusMessage').textContent =
                        `Characters match at index ${charIndex}, checking next character...`;
                    charIndex++;
                } else if (pos1 < pos2) {
                    document.getElementById('comparisonContainer').innerHTML =
                        `Comparing char[${charIndex}]: '${c1}' (pos ${pos1}) < '${c2}' (pos ${pos2}) → ✓ Correct order!`;
                    document.getElementById('statusMessage').textContent =
                        `'${c1}' comes before '${c2}' in alien order. This pair is valid!`;
                    // Move to next pair
                    currentPair++;
                    charIndex = 0;
                    document.querySelectorAll('[id^="word-"]').forEach(b => b.classList.remove('current'));
                    if (currentPair < words.length - 1) {
                        document.getElementById(`word-${currentPair}`).classList.add('current');
                        document.getElementById(`word-${currentPair + 1}`).classList.add('current');
                    }
                } else {
                    document.getElementById('comparisonContainer').innerHTML =
                        `Comparing char[${charIndex}]: '${c1}' (pos ${pos1}) > '${c2}' (pos ${pos2}) → ❌ Wrong order!`;
                    phase = 'done';
                    document.getElementById('resultBox').style.display = 'block';
                    document.getElementById('resultBox').className = 'info-box highlight';
                    document.getElementById('resultBox').textContent = `❌ NOT SORTED! '${c1}' comes after '${c2}' in alien order.`;
                    document.getElementById('stepBtn').disabled = true;
                    stopAuto();
                }
            }
        }

        function toggleAuto() {
            if (autoInterval) {
                stopAuto();
            } else {
                document.getElementById('autoBtn').textContent = 'Pause';
                autoInterval = setInterval(() => {
                    if (phase === 'done') {
                        stopAuto();
                    } else {
                        step();
                    }
                }, 1200);
            }
        }

        function stopAuto() {
            if (autoInterval) {
                clearInterval(autoInterval);
                autoInterval = null;
            }
            document.getElementById('autoBtn').textContent = 'Auto Run';
        }

        function reset() {
            stopAuto();
            phase = 'init';
            currentPair = 0;
            charIndex = 0;
            document.getElementById('stepBtn').disabled = false;
            document.getElementById('statusMessage').textContent =
                'Click "Step" or "Auto Run" to check if words are sorted in alien order';
            document.querySelectorAll('.array-box').forEach(b => {
                b.classList.remove('highlight', 'current', 'complete');
            });
            init();
        }

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