Files
illustrated-algorithm/palindrome-linked-list/index.html
T
2026-08-24 04:35:13 +00:00

200 lines
9.2 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
<!DOCTYPE html>
<html lang="zh-Hans">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>024. 回文链表 – 图解</title>
<link rel="stylesheet" href="../shared/style.css">
<style>
/* page-specific overrides */
.vis-area { min-height: 120px; padding: 16px 0; }
.code-section { margin-top: 16px; }
</style>
</head>
<body>
<div class="container">
<h1>🟢 024. 回文链表 <span class="badge easy">简单</span></h1>
<p class="subtitle">分类:链表 | LeetCode Hot 100</p>
<!-- 控制面板 -->
<div class="controls" id="controls">
<label for="inputArea">输入:</label>
<input type="text" id="inputArea" placeholder="默认示例,可自定义">
<button id="applyBtn" class="primary">生成图解</button>
<select id="exampleSelect"></select>
<span style="flex:1"></span>
<button id="prevBtn">◀ 上一步</button>
<button id="nextBtn">下一步 ▶</button>
<button id="jumpBtn">⏭ 跳到结果</button>
<button id="autoBtn">自动播放</button>
<button id="resetBtn">重置</button>
</div>
<!-- 步骤流水线 -->
<div class="pipeline" id="pipeline"></div>
<!-- 提示条 -->
<div class="hint info" id="hintBox">
<span id="stepInfo"></span><br>
<span id="hintText"></span>
</div>
<!-- 可视化面板 -->
<div class="panels">
<div class="panel" id="mainPanel">
<h3>📊 可视化</h3>
<div class="vis-area" id="vizArea">点击「生成图解」开始</div>
</div>
<div class="panel-grid">
<div class="panel" id="detailPanel">
<h3>📝 当前步骤详情</h3>
<div id="detailContent">等待开始...</div>
</div>
<div class="panel" id="resultPanel">
<h3>✅ 结果</h3>
<div id="resultContent">等待完成...</div>
</div>
</div>
</div>
<!-- 代码 -->
<div class="panel code-section">
<h3>💻 参考代码(Python)</h3>
<div id="codeArea"></div>
</div>
<footer>Powered by QwenPaw · 图解算法 · LeetCode Hot 100</footer>
</div>
<script src="../shared/algo-viz.js"></script>
<script>
"use strict";
(function() {
// ========== Algorithm Logic ==========
function llViz(nodes, opts) {
opts = opts || {};
var highs = opts.highs || {};
var ptrs = opts.ptrs || {};
var cycle = opts.cycle != null ? opts.cycle : -1;
var label = opts.label || '';
var showNull = opts.showNull !== false;
var html = '';
if (label) html += '<div style="font-size:13px;font-weight:600;color:var(--text-secondary);margin-bottom:4px;">' + label + '</div>';
html += '<div style="display:flex;flex-wrap:wrap;align-items:center;gap:4px;padding:4px 0;">';
for (var i = 0; i < nodes.length; i++) {
var cls = highs[i] || '';
html += '<div style="position:relative;display:inline-flex;flex-direction:column;align-items:center;">';
html += '<div class="ll-node ' + cls + '">';
html += '<span class="val">' + nodes[i] + '</span>';
if (i === cycle) {
html += '<span class="arrow" style="color:var(--red);font-weight:bold;">&#8617;</span>';
} else if (i < nodes.length - 1) {
html += '<span class="arrow">&rarr;</span>';
} else if (showNull && i === nodes.length - 1) {
html += '<span class="arrow" style="color:var(--text-muted);">&empty;</span>';
}
html += '</div>';
var plabels = [];
var pkeys = Object.keys(ptrs);
for (var pi = 0; pi < pkeys.length; pi++) {
if (ptrs[pkeys[pi]] === i) plabels.push(pkeys[pi]);
}
if (plabels.length) {
html += '<div style="font-size:10px;font-weight:700;color:var(--blue);margin-top:2px;white-space:nowrap;">' + plabels.join(',') + '</div>';
}
html += '</div>';
}
html += '</div>';
return html;
}
function setPipeline(stages, current) {
$('pipeline').innerHTML = stages.map(function(st) {
var parts = st.split('\u2192');
return '<span class="pipe-step ' + (current===parts[0]?'active':'') + '">' + parts[1] + '</span>';
}).join('<i>\u2192</i>');
}
var examples = [
{input:[1,2,2,1], label:'示例1: [1,2,2,1] 回文'},
{input:[1,2], label:'示例2: [1,2] 非回文'},
{input:[1,2,3,2,1], label:'示例3: [1,2,3,2,1] 回文'},
];
var nodes, steps, stepCtrl;
function buildSteps(arr) {
nodes = arr.slice(); steps = [];
if (arr.length === 0) { steps.push({stage:'done',msg:'空链表是回文',phase:'done'}); return; }
steps.push({stage:'init', msg:'快慢指针找中点 + 反转后半部分 + 比较', phase:'find_mid', slow:0, fast:0});
// Phase 1: find middle
var slow = 0, fast = 0;
while (fast < arr.length - 1 && fast + 1 < arr.length - 1) {
slow++; fast += 2;
steps.push({stage:'move', msg:'slow→'+arr[slow]+', fast→'+arr[Math.min(fast,arr.length-1)], phase:'find_mid', slow:slow, fast:Math.min(fast,arr.length-1)});
}
var mid = slow + 1;
steps.push({stage:'mid', msg:'中点后半起始位置:index ' + mid + ' (值=' + arr[mid] + ')', phase:'find_mid', slow:slow, fast:Math.min(fast,arr.length-1), mid:mid});
// Phase 2: reverse second half
var second = arr.slice(mid);
var reversed = second.slice().reverse();
steps.push({stage:'reverse', msg:'反转后半 [' + second.join(',') + '] → [' + reversed.join(',') + ']', phase:'reverse', second:second.slice(), reversed:reversed.slice()});
// Phase 3: compare
var first = arr.slice(0, arr.length - second.length);
var isPalin = true;
for (var i = 0; i < reversed.length; i++) {
if (first[i] !== reversed[i]) { isPalin = false; break; }
}
steps.push({stage:'compare', msg:'前半 ['+first.join(',')+'] vs 反转后半 ['+reversed.join(',')+'] → ' + (isPalin?'匹配 ✓':'不匹配 ✗'), phase:'compare', first:first, reversed:reversed, isPalin:isPalin});
steps.push({stage:'done', msg:'结果:' + (isPalin?'是回文链表':'不是回文链表'), phase:'done', isPalin:isPalin});
}
function render(step) {
var s = steps[step];
var viz = '';
if (s.phase === 'find_mid' || s.stage === 'init') {
var hl = {};
if (s.slow >= 0 && s.slow < nodes.length) hl[s.slow] = 'active';
if (s.fast >= 0 && s.fast < nodes.length) hl[s.fast] = 'current';
viz = llViz(nodes, {highs:hl, ptrs:{slow:s.slow, fast:s.fast}, label:'寻找中点'});
} else if (s.phase === 'reverse') {
viz = llViz(nodes, {highs:{}, label:'原始链表'});
viz += llViz(s.reversed, {highs:{}, label:'反转后半', showNull:false});
} else if (s.phase === 'compare' || s.phase === 'done') {
viz = llViz(s.first, {label:'前半部分', showNull:false});
viz += llViz(s.reversed, {label:'反转后半', showNull:false});
viz += '<div style="margin-top:8px;font-size:15px;">' + (s.isPalin ? '<span style="color:var(--green);font-weight:700;">✓ 匹配</span>' : '<span style="color:var(--red);font-weight:700;">✗ 不匹配</span>') + '</div>';
}
$('vizArea').innerHTML = viz;
$('detailContent').innerHTML = '<div class="calc-block">' + s.msg + '</div>';
if (s.stage === 'done') {
$('resultContent').innerHTML = '<div class="final-answer">' + (s.isPalin?'是回文链表 ✓':'不是回文链表 ✗') + '</div>';
}
$('hintText').textContent = s.msg;
setPipeline(['init\u2192开始','move\u2192快慢','mid\u2192中点','reverse\u2192反转','compare\u2192比较','done\u2192结果'], s.stage);
}
function init() {
var sel = $('exampleSelect');
examples.forEach(function(e,i){ sel.innerHTML += '<option value="'+i+'">'+e.label+'</option>'; });
$('inputArea').value = '[1,2,2,1]';
buildSteps(examples[0].input);
stepCtrl = new StepController({onStep:render});
stepCtrl.setSteps(steps.map(function(_,i){return i;}));
$('stepInfo').textContent = '步骤 1 / ' + steps.length;
stepCtrl.onStep = function(idx){ render(idx); $('stepInfo').textContent = '步骤 '+(idx+1)+' / '+steps.length; };
$('applyBtn').onclick = function(){ try { var arr=JSON.parse($('inputArea').value); buildSteps(arr); stepCtrl.setSteps(steps.map(function(_,i){return i;})); render(0); } catch(e){ alert('请输入合法 JSON 数组'); } };
$('exampleSelect').onchange = function(){ buildSteps(examples[parseInt($('exampleSelect').value)].input); stepCtrl.setSteps(steps.map(function(_,i){return i;})); render(0); };
$('prevBtn').onclick = function(){ stepCtrl.prev(); };
$('nextBtn').onclick = function(){ stepCtrl.next(); };
$('jumpBtn').onclick = function(){ stepCtrl.jumpToEnd(); };
$('autoBtn').onclick = function(){ var on=stepCtrl.toggleAuto(); $('autoBtn').textContent=on?'暂停':'自动播放'; };
$('resetBtn').onclick = function(){ stepCtrl.reset(); $('autoBtn').textContent='自动播放'; };
}
init();
$('codeArea').innerHTML = renderCode('def isPalindrome(head):\n slow = fast = head\n while fast and fast.next:\n slow = slow.next\n fast = fast.next.next\n prev = None\n while slow:\n nxt = slow.next\n slow.next = prev\n prev = slow\n slow = nxt\n left, right = head, prev\n while right:\n if left.val != right.val:\n return False\n left = left.next\n right = right.next\n return True', {lang:'Python'});
})();
</script>
</body>
</html>