GraphSimulation/dfs.html at master · harshpalas/GraphSimulation · 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" />
  <title>Graph DFS Visualizer - Multiple Graphs with Explanation</title>
  <script src="https://cdn.tailwindcss.com"></script>
  <style>

    #explanation {
      background: #1e293b;
      border-radius: 0.5rem;
      padding: 1rem;
      height: 220px;
      overflow-y: auto;
      font-family: monospace;
      white-space: pre-wrap;
      line-height: 1.5;
      font-size: 15px;
      margin-top: 1rem;
      box-shadow: inset 0 0 8px #334155;
    }
    /* Typewriter effect cursor */
    .cursor {
      display: inline-block;
      background-color: #3b82f6;
      width: 8px;
      animation: blink 1s infinite;
      vertical-align: bottom;
      margin-left: 2px;
      border-radius: 2px;
    }
    @keyframes blink {
      0%, 50% { opacity: 1; }
      51%, 100% { opacity: 0; }
    }
  </style>
</head>
<body class="bg-gray-900 text-white min-h-screen flex items-center justify-center p-4">
  <div class="p-6 bg-gray-800 rounded-xl shadow-xl w-[1400px] max-w-full">
    <div class="flex gap-6 flex-wrap">
      <!-- Sidebar -->
      <div class="w-64 flex flex-col gap-4">
        <h2 class="text-2xl font-bold mb-2">DFS Visualizer (Multiple Graphs)</h2>
        <label>
          Start Node:
          <select id="start" class="w-full text-black rounded p-2 mt-1"></select>
        </label>
        <button id="run" class="bg-blue-600 hover:bg-blue-700 text-white py-2 px-4 rounded">Run DFS</button>
        <button id="reset" class="bg-gray-400 hover:bg-gray-500 text-white py-2 px-4 rounded">Reset</button>
        <button id="changeGraph" class="bg-green-600 hover:bg-green-700 text-white py-2 px-4 rounded">Change Graph</button>
        <button id="playPause" class="bg-purple-600 hover:bg-purple-700 text-white py-2 px-4 rounded mt-2">Play</button>
        <p id="orderDisplay" class="text-sm text-gray-300 mt-4">DFS Order: </p>
        <p id="graphName" class="text-gray-400 mt-2"></p>


        <div id="explanation" tabindex="0" aria-label="DFS explanation text" role="log" aria-live="polite"></div>
      </div>

      <!-- Graph Area -->
      <div class="flex-1 overflow-auto max-w-[1100px]">
        <svg id="graph" width="1100" height="700" class="rounded bg-gray-700 shadow"></svg>
      </div>
    </div>
  </div>

<script>

const graphs = [
  {
    name: "Binary Tree (31 nodes)",
    totalNodes: 31,
    positions: (() => {
      const positions = [];
      const levels = 5;
      const width = 1100;
      const verticalSpacing = 110;
      for (let level = 0; level < levels; level++) {
        const nodesInLevel = Math.pow(2, level);
        const horizontalSpacing = width / (nodesInLevel + 1);
        for (let i = 0; i < nodesInLevel; i++) {
          const x = horizontalSpacing * (i + 1);
          const y = verticalSpacing * level + 50;
          positions.push({ x, y });
        }
      }
      return positions;
    })(),
    edges: (() => {
      const edges = [];
      const totalNodes = 31;
      for (let i = 0; i < totalNodes; i++) {
        const left = 2 * i + 1;
        const right = 2 * i + 2;
        if (left < totalNodes) edges.push([i, left]);
        if (right < totalNodes) edges.push([i, right]);
      }
      return edges;
    })()
  },
  {
    name: "Grid Graph (5x5 = 25 nodes)",
    totalNodes: 25,
    positions: (() => {
      const positions = [];
      const rows = 5;
      const cols = 5;
      const spacingX = 180;
      const spacingY = 120;
      const startX = 100;
      const startY = 100;
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
          positions.push({ x: startX + c * spacingX, y: startY + r * spacingY });
        }
      }
      return positions;
    })(),
    edges: (() => {
      const edges = [];
      const rows = 5;
      const cols = 5;
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
          const idx = r * cols + c;
          // right neighbor
          if (c + 1 < cols) edges.push([idx, idx + 1]);
          // down neighbor
          if (r + 1 < rows) edges.push([idx, idx + cols]);
        }
      }
      return edges;
    })()
  }
];

let currentGraphIndex = 0;
let graph = graphs[currentGraphIndex];
let adj = [];
let animOrder = [];
let visitedEdges = new Set();

const radius = 18;

let play = false;
let pauseResolve = null;

function buildAdjacency() {
  adj = Array.from({ length: graph.totalNodes }, () => []);
  graph.edges.forEach(([u, v]) => {
    adj[u].push(v);
    adj[v].push(u);
  });
}

function drawGraph() {
  const svg = document.getElementById("graph");
  svg.innerHTML = "";


  for (let [u, v] of graph.edges) {
    const p1 = graph.positions[u];
    const p2 = graph.positions[v];
    const edgeId1 = `${u}-${v}`;
    const edgeId2 = `${v}-${u}`;
    const isVisitedEdge = visitedEdges.has(edgeId1) || visitedEdges.has(edgeId2);

    const line = document.createElementNS("http://www.w3.org/2000/svg", "line");
    line.setAttribute("x1", p1.x);
    line.setAttribute("y1", p1.y);
    line.setAttribute("x2", p2.x);
    line.setAttribute("y2", p2.y);
    line.setAttribute("stroke", isVisitedEdge ? "#3b82f6" : "#ccc");
    line.setAttribute("stroke-width", isVisitedEdge ? "5" : "2");
    svg.appendChild(line);
  }

  // Draw nodes
  for (let i = 0; i < graph.totalNodes; i++) {
    const { x, y } = graph.positions[i];
    const circle = document.createElementNS("http://www.w3.org/2000/svg", "circle");
    circle.setAttribute("cx", x);
    circle.setAttribute("cy", y);
    circle.setAttribute("r", radius);
    circle.setAttribute("fill", animOrder.includes(i) ? "#3b82f6" : "#e2e8f0");
    circle.setAttribute("stroke", "#1e293b");
    circle.setAttribute("stroke-width", "2");
    svg.appendChild(circle);

    const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
    text.setAttribute("x", x);
    text.setAttribute("y", y + 6);
    text.setAttribute("text-anchor", "middle");
    text.setAttribute("font-size", "16");
    text.setAttribute("font-weight", "bold");
    text.setAttribute("fill", animOrder.includes(i) ? "#fff" : "#000");
    text.textContent = i;
    svg.appendChild(text);
  }
}

function fillSelects() {
  const startSel = document.getElementById("start");
  startSel.innerHTML = "";
  for (let i = 0; i < graph.totalNodes; i++) {
    const opt = document.createElement("option");
    opt.value = i;
    opt.textContent = i;
    startSel.appendChild(opt);
  }
}

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

// --- TYPEWRITER FUNCTION ---
// Types out the given text letter by letter inside the given element
async function typeWriterEffect(element, text, speed = 20) {
  element.textContent = ""; // clear
  for (let i = 0; i < text.length; i++) {
    // Wait if paused
    await waitIfPaused();

    element.textContent += text.charAt(i);
    // Add blinking cursor effect:
    // We'll add a span cursor after text, removed/readded to simulate blinking
    if (!element.querySelector(".cursor")) {
      const cursor = document.createElement("span");
      cursor.className = "cursor";
      element.appendChild(cursor);
    }
    await sleep(speed);
  }
  // Remove cursor after done typing
  const cursor = element.querySelector(".cursor");
  if (cursor) cursor.remove();
}

// Waits if play = false, resolves when play = true
function waitIfPaused() {
  if (play) return Promise.resolve();
  return new Promise(resolve => (pauseResolve = resolve));
}

// Resolves pause when toggled play on
function resumeIfPaused() {
  if (pauseResolve) {
    pauseResolve();
    pauseResolve = null;
  }
}

const explanationContainer = document.getElementById("explanation");

function appendExplanationLine(text) {
  const line = document.createElement("div");
  explanationContainer.appendChild(line);
  // Scroll to bottom after next frame
  setTimeout(() => {
    explanationContainer.scrollTop = explanationContainer.scrollHeight;
  }, 50);
  return line;
}

async function runDFS(start) {
  const visited = Array(graph.totalNodes).fill(false);
  animOrder = [];
  visitedEdges.clear();

  explanationContainer.innerHTML = ""; // clear explanations on new run
  updateOrderDisplay();

  async function dfs(u) {
    // Explanation line for visiting node
    let line = appendExplanationLine(`Visiting node ${u}...`);
    await typeWriterEffect(line, `Visiting node ${u}...`, 30);

    visited[u] = true;
    animOrder.push(u);
    drawGraph();
    updateOrderDisplay();

    await sleep(400);

    for (const v of adj[u]) {
      if (!visited[v]) {
        // Explain edge traversal
        line = appendExplanationLine(`Going deeper from node ${u} to ${v}...`);
        await typeWriterEffect(line, `Going deeper from node ${u} to ${v}...`, 30);

        visitedEdges.add(`${u}-${v}`);
        drawGraph();
        await sleep(400);

        await dfs(v);
      } else {
        // Explain skipping visited
        line = appendExplanationLine(`Node ${v} already visited, skipping...`);
        await typeWriterEffect(line, `Node ${v} already visited, skipping...`, 30);
        await sleep(300);
      }
    }
    // After exploring all neighbors
    line = appendExplanationLine(`Backtracking from node ${u}...`);
    await typeWriterEffect(line, `Backtracking from node ${u}...`, 30);
    await sleep(300);
  }

  await dfs(start);

  const doneLine = appendExplanationLine("DFS Complete!");
  await typeWriterEffect(doneLine, "DFS Complete!", 30);

  play = false;
  updatePlayPauseButton();
}

function updateOrderDisplay() {
  document.getElementById("orderDisplay").textContent = `DFS Order: ${animOrder.join(" → ")}`;
  document.getElementById("graphName").textContent = `Current Graph: ${graph.name}`;
}

function resetAll() {
  animOrder = [];
  visitedEdges.clear();
  explanationContainer.innerHTML = "";
  drawGraph();
  updateOrderDisplay();
  play = false;
  updatePlayPauseButton();
  resumeIfPaused();
}

function updatePlayPauseButton() {
  const btn = document.getElementById("playPause");
  btn.textContent = play ? "Pause" : "Play";
}

document.addEventListener("DOMContentLoaded", () => {
  buildAdjacency();
  fillSelects();
  drawGraph();
  updateOrderDisplay();

  document.getElementById("run").onclick = async () => {
    if (play) return; // Prevent double run
    animOrder = [];
    visitedEdges.clear();
    play = true;
    updatePlayPauseButton();

    const start = +document.getElementById("start").value;
    await runDFS(start);
  };

  document.getElementById("reset").onclick = () => {
    resetAll();
  };

  document.getElementById("changeGraph").onclick = () => {
    currentGraphIndex = (currentGraphIndex + 1) % graphs.length;
    graph = graphs[currentGraphIndex];
    animOrder = [];
    visitedEdges.clear();
    buildAdjacency();
    fillSelects();
    resetAll();
  };

  document.getElementById("playPause").onclick = () => {
    play = !play;
    updatePlayPauseButton();
    if (play) {
      resumeIfPaused();
    }
  };
});
</script>
</body>
</html>