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illustrated-algorithm/maximum-product-subarray/index.html
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<!DOCTYPE html>
<html lang="zh-Hans">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>088. 乘积最大子数组 – 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>🟡 088. 乘积最大子数组 <span class="badge medium">中等</span></h1>
<p class="subtitle">分类:动态规划 | 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 ==========
const examples = [
{input: [2,3,-2,4], label: '示例1: [2,3,-2,4]'},
{input: [-2,0,-1], label: '示例2: [-2,0,-1]'},
{input: [-2,3,-4], label: '示例3: [-2,3,-4]'},
];
let nums, steps, stepCtrl;
function buildSteps(arr) {
nums = [...arr]; steps = [];
const n = nums.length;
const maxDP = new Array(n).fill(0);
const minDP = new Array(n).fill(0);
maxDP[0] = nums[0]; minDP[0] = nums[0];
let globalMax = nums[0];
steps.push({stage:'init', msg:`maxDP[0]=${nums[0]},minDP[0]=${nums[0]}(同时维护最大和最小)`, maxDP:[...maxDP], minDP:[...minDP], current:-1, globalMax, candidates:null});
for (let i = 1; i < n; i++) {
const candidates = [nums[i], maxDP[i-1]*nums[i], minDP[i-1]*nums[i]];
maxDP[i] = Math.max(...candidates);
minDP[i] = Math.min(...candidates);
globalMax = Math.max(globalMax, maxDP[i]);
steps.push({stage:'calc', msg:`nums[${i}]=${nums[i]}:候选值 = [${nums[i]}, ${maxDP[i-1]}×${nums[i]}=${candidates[1]}, ${minDP[i-1]}×${nums[i]}=${candidates[2]}]`, maxDP:[...maxDP], minDP:[...minDP], current:i, globalMax, candidates});
steps.push({stage:'fill', msg:`maxDP[${i}]=${maxDP[i]},minDP[${i}]=${minDP[i]},全局最大=${globalMax}`, maxDP:[...maxDP], minDP:[...minDP], current:i, globalMax, candidates});
}
steps.push({stage:'done', msg:`乘积最大子数组的积 = ${globalMax}`, maxDP:[...maxDP], minDP:[...minDP], current:n-1, globalMax, candidates:null});
}
function render(step) {
const s = steps[step];
const hl = {};
if (s.current >= 0) hl[s.current] = 'orange';
let viz = renderArray(nums, {highlights: hl});
viz += '<div style="margin-top:12px;"><b>maxDP(最大乘积):</b></div>';
const maxHl = {};
if (s.current >= 0) maxHl[s.current] = 'green';
viz += renderArray(s.maxDP, {highlights: maxHl});
viz += '<div style="margin-top:8px;"><b>minDP(最小乘积):</b></div>';
const minHl = {};
if (s.current >= 0) minHl[s.current] = 'purple';
viz += renderArray(s.minDP, {highlights: minHl});
if (s.candidates) {
viz += '<div style="margin-top:8px;"><b>三个候选:</b></div>';
viz += '<div style="display:flex;gap:8px;margin:4px 0;">';
const labels = ['当前数', 'maxDP×当前', 'minDP×当前'];
s.candidates.forEach((c, idx) => {
const isMax = c === s.maxDP[s.current];
const isMin = c === s.minDP[s.current];
let bd = '1px solid #cbd5e1', bg = '#f8fafc';
if (isMax && isMin) { bd = '2px solid #8b5cf6'; bg = '#ede9fe'; }
else if (isMax) { bd = '2px solid #16a34a'; bg = '#dcfce7'; }
else if (isMin) { bd = '2px solid #7c3aed'; bg = '#ede9fe'; }
viz += `<span style="padding:4px 10px;background:${bg};border:${bd};border-radius:8px;font-size:13px;">${labels[idx]}=<b>${c}</b></span>`;
});
viz += '</div>';
}
$('vizArea').innerHTML = viz;
$('detailContent').innerHTML = '<div class="calc-block">' + s.msg + '</div>';
$('detailContent').innerHTML += `<div class="current-answer">全局最大乘积:<b>${s.globalMax}</b></div>`;
if (s.stage === 'done') {
$('resultContent').innerHTML = `<div class="final-answer">乘积最大子数组的积 = <b>${s.globalMax}</b></div>`;
}
$('hintText').textContent = s.msg;
const stages = ['init→初始化','calc→计算','fill→填充','done→完成'];
$('pipeline').innerHTML = stages.map(st => {
const [k,l] = st.split('→');
return `<span class="pipe-step ${s.stage===k?'active':''}">${l}</span>`;
}).join('<i>→</i>');
}
function init() {
const sel = $('exampleSelect');
examples.forEach((e,i) => { sel.innerHTML += `<option value="${i}">${e.label}</option>`; });
$('inputArea').value = '[2,3,-2,4]';
buildSteps(examples[0].input);
stepCtrl = new StepController({onStep: render});
stepCtrl.setSteps(steps.map((_,i)=>i));
$('stepInfo').textContent = '步骤 1 / ' + steps.length;
stepCtrl.onStep = (idx) => { render(idx); $('stepInfo').textContent = `步骤 ${idx+1} / ${steps.length}`; };
$('applyBtn').onclick = () => {
try { const arr = JSON.parse($('inputArea').value); buildSteps(arr); stepCtrl.setSteps(steps.map((_,i)=>i)); render(0); $('stepInfo').textContent = '步骤 1 / ' + steps.length; }
catch(e) { alert('请输入合法 JSON 数组'); }
};
$('exampleSelect').onchange = () => {
const e = examples[parseInt($('exampleSelect').value)];
$('inputArea').value = JSON.stringify(e.input);
buildSteps(e.input); stepCtrl.setSteps(steps.map((_,i)=>i)); render(0);
};
$('prevBtn').onclick = () => stepCtrl.prev();
$('nextBtn').onclick = () => stepCtrl.next();
$('jumpBtn').onclick = () => stepCtrl.jumpToEnd();
$('autoBtn').onclick = () => { const on = stepCtrl.toggleAuto(); $('autoBtn').textContent = on ? '暂停' : '自动播放'; };
$('resetBtn').onclick = () => { stepCtrl.reset(); $('autoBtn').textContent = '自动播放'; };
}
init();
$('codeArea').innerHTML = renderCode(`def maxProduct(nums):
max_dp = min_dp = result = nums[0]
for i in range(1, len(nums)):
candidates = (nums[i], max_dp * nums[i], min_dp * nums[i])
max_dp = max(candidates)
min_dp = min(candidates)
result = max(result, max_dp)
return result`, {lang:'Python'});
})();
</script>
</body>
</html>