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illustrated-algorithm/number-of-islands/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>051. 岛屿数量 – 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>🟡 051. 岛屿数量 <span class="badge medium">中等</span></h1>
<p class="subtitle">分类:图论 | 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 = [
{grid: [["1","1","0","0","0"],["1","1","0","0","0"],["0","0","1","0","0"],["0","0","0","1","1"]], label: '示例1: 4×5 3个岛'},
{grid: [["1","1","1"],["0","1","0"],["1","1","1"]], label: '示例2: 3×3 1个岛'},
];
let grid, R, C, steps, stepCtrl, islandColors, finalMap;
function buildSteps(g) {
grid = g.map(r=>[...r]); R = grid.length; C = grid[0].length;
steps = []; islandColors = {}; finalMap = {};
const visited = Array.from({length:R},()=>Array(C).fill(false));
let islands = 0;
const islandColorList = ['blue','green','purple','orange','cyan','red'];
steps.push({stage:'start', msg:'遍历网格,遇到未访问的陆地进行DFS染色', hl:{}, im:{}, islands:0});
for (let r=0; r<R; r++) {
for (let c=0; c<C; c++) {
if (grid[r][c]==='1' && !visited[r][c]) {
islands++;
const color = islandColorList[(islands-1) % islandColorList.length];
islandColors[islands] = color;
steps.push({stage:'new_island', msg:`发现岛屿 #${islands},从 (${r},${c}) 开始DFS`, hl:{[r+','+c]:'current'}, im:JSON.parse(JSON.stringify(finalMap)), islands});
const stack = [[r,c]];
visited[r][c] = true;
finalMap[r+','+c] = islands;
while (stack.length > 0) {
const [cr, cc] = stack.pop();
const dirs = [[0,1],[0,-1],[1,0],[-1,0]];
for (const [dr,dc] of dirs) {
const nr=cr+dr, nc=cc+dc;
if (nr>=0 && nr<R && nc>=0 && nc<C && grid[nr][nc]==='1' && !visited[nr][nc]) {
visited[nr][nc] = true;
stack.push([nr,nc]);
finalMap[nr+','+nc] = islands;
const hl2 = {}; hl2[nr+','+nc] = 'current';
steps.push({stage:'dfs', msg:`DFS: (${cr},${cc}) → (${nr},${nc}) 染色为岛 #${islands}`, hl:hl2, im:JSON.parse(JSON.stringify(finalMap)), islands});
}
}
}
steps.push({stage:'island_done', msg:`岛屿 #${islands} DFS完成`, hl:{}, im:JSON.parse(JSON.stringify(finalMap)), islands});
}
}
}
steps.push({stage:'done', msg:`遍历完毕,共 ${islands} 个岛屿`, hl:{}, im:JSON.parse(JSON.stringify(finalMap)), islands});
}
function render(step) {
const s = steps[step];
const cellClass = (val,r,c) => {
if (val==='0') return 'water';
const key = r+','+c;
const iid = s.im[key];
if (iid) return islandColors[iid] || 'island';
return 'default';
};
const cellStyle = (val,r,c) => {
if (val==='0') return 'background:#e0f2fe;color:#0369a1;';
const key = r+','+c;
const iid = s.im[key];
const colorMap = {blue:'background:#dbeafe;color:#1e40af;',green:'background:#dcfce7;color:#166534;',purple:'background:#ede9fe;color:#5b21b6;',orange:'background:#fff7ed;color:#9a3412;',cyan:'background:#cffafe;color:#155e75;',red:'background:#fee2e2;color:#991b1b;'};
if (iid && colorMap[islandColors[iid]]) return colorMap[islandColors[iid]];
return 'background:#f1f5f9;color:#475569;';
};
let viz = renderGrid(grid, {highlights:s.hl, cellSize:48, cellClass, cellStyle});
viz += `<div style="margin-top:8px;">🏝️ 岛屿数量:${s.islands}</div>`;
$('vizArea').innerHTML = viz;
$('detailContent').innerHTML = '<div class="calc-block">' + s.msg + '</div>';
if (s.stage==='done') {
let det = `<div class="final-answer">岛屿数量 = <b>${s.islands}</b></div>`;
det += '<div style="margin-top:8px;">';
for (let i=1; i<=s.islands; i++) det += `<span style="margin-right:12px;"><span style="display:inline-block;width:14px;height:14px;border-radius:3px;${islandColors[i]==='blue'?'background:#dbeafe':islandColors[i]==='green'?'background:#dcfce7':islandColors[i]==='purple'?'background:#ede9fe':'background:#fff7ed'};vertical-align:middle;"></span> 岛屿 #${i}</span>`;
det += '</div>';
$('resultContent').innerHTML = det;
}
$('hintText').textContent = s.msg;
const stages = ['start→开始','new_island→发现岛屿','dfs→DFS染色','island_done→岛屿完成','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 = '[["1","1","0"],["0","1","0"],["0","0","1"]]';
buildSteps(examples[0].grid);
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}`; };
$('applyBtn').onclick = () => {
try { const g = JSON.parse($('inputArea').value); buildSteps(g); stepCtrl.setSteps(steps.map((_,i)=>i)); render(0); $('stepInfo').textContent = '步骤 1 / ' + steps.length; }
catch(e) { alert('请输入合法 JSON 二维数组'); }
};
$('exampleSelect').onchange = () => {
const e = examples[parseInt($('exampleSelect').value)];
buildSteps(e.grid); 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 numIslands(grid):
if not grid: return 0
rows, cols = len(grid), len(grid[0])
def dfs(r, c):
if r<0 or r>=rows or c<0 or c>=cols or grid[r][c]!='1':
return
grid[r][c] = '2'
dfs(r+1,c); dfs(r-1,c)
dfs(r,c+1); dfs(r,c-1)
islands = 0
for r in range(rows):
for c in range(cols):
if grid[r][c] == '1':
islands += 1
dfs(r, c)
return islands`, {lang:'Python'});
})();
</script>
</body>
</html>