GraphSimulation/dj.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>Dijkstra Visualizer</title>
<script src="https://cdn.tailwindcss.com"></script>
<style>
  #explanation {
    scrollbar-width: thin;
    scrollbar-color: #60a5fa #1e293b;
  }
  #explanation::-webkit-scrollbar {
    width: 8px;
  }
  #explanation::-webkit-scrollbar-thumb {
    background-color: #60a5fa;
    border-radius: 4px;
  }


  @media (max-width: 1100px) {
    .container-flex {
      flex-direction: column;
    }
    #graph {
      width: 100% !important;
      height: 500px !important;
      margin-top: 16px;
    }
    .sidebar {
      width: 100% !important;
      max-width: none !important;
      margin-bottom: 16px;
    }
  }
</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-full max-w-[1400px] flex container-flex gap-6 flex-wrap">
    <!-- Sidebar -->
    <div class="sidebar w-64 flex flex-col gap-4 flex-shrink-0">
      <h2 class="text-2xl font-bold mb-2">Dijkstra Visualizer</h2>
      <label>
        Start Node:
        <select id="start" class="w-full text-black rounded p-2 mt-1"></select>
      </label>
      <label>
        End Node:
        <select id="end" 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</button>
      <button id="reset" class="bg-gray-400 hover:bg-gray-500 text-white py-2 px-4 rounded">Reset</button>
      <button id="toggle" class="bg-yellow-500 hover:bg-yellow-600 text-white py-2 px-4 rounded">Pause</button>
      <p id="pathDisplay" class="text-sm text-gray-300 mt-2">Shortest Path: </p>
      <div id="explanation" class="text-sm text-blue-300 mt-2 max-h-80 overflow-auto p-2 bg-gray-900 rounded"></div>
    </div>


    <div class="flex-1 min-w-[300px]">
      <svg id="graph" width="1000" height="700" class="rounded bg-gray-700 shadow w-full h-[700px]"></svg>
    </div>
  </div>

<script>
const positions = [
  {x: 100, y: 350}, {x: 200, y: 250}, {x: 200, y: 450},
  {x: 300, y: 350}, {x: 400, y: 150}, {x: 400, y: 350},
  {x: 400, y: 550}, {x: 600, y: 250}, {x: 600, y: 450}, {x: 750, y: 350},
];

const edges = [
  [0, 1], [0, 2], [0, 3], [1, 2], [1, 3], [2, 3], [2, 6],
  [3, 4], [3, 5], [3, 6], [4, 5], [4, 7], [5, 6], [5, 7], [5, 8], [6, 8], [7, 9], [8, 9]
];

// Create adjacency matrix with weights
let graph = Array.from({ length: 10 }, () => Array(10).fill(Infinity));
edges.forEach(([u, v]) => {
  const w = Math.floor(Math.random() * 20) + 5;
  graph[u][v] = w;
  graph[v][u] = w;
});

class PriorityQueue {
  constructor() { this.data = []; }
  enqueue(val, pri) {
    this.data.push({ val, pri });
    this.data.sort((a, b) => a.pri - b.pri);
  }
  dequeue() { return this.data.shift()?.val; }
  isEmpty() { return this.data.length === 0; }
}

let animPath = [];
let distMemory = [];
let isPaused = false;
let toggleBtn;

function sleep(ms) {
  return new Promise(resolve => {
    const check = () => {
      if (!isPaused) {
        resolve();
      } else {
        setTimeout(check, 100);
      }
    };
    setTimeout(check, ms);
  });
}

async function typeExplanation(text) {
  const explanationDiv = document.getElementById("explanation");
  return new Promise(async (resolve) => {
    let para = document.createElement("p");
    explanationDiv.appendChild(para);

    for (let i = 0; i < text.length; i++) {
      while (isPaused) {
        await sleep(100);
      }
      para.textContent += text[i];
      explanationDiv.scrollTop = explanationDiv.scrollHeight;
      await sleep(80);  // Slowed down here from 40ms to 80ms
    }
    resolve();
  });
}

function drawGraph(highlightedEdges = [], distMap = [], currentNode = null, finalHighlight = false) {
  const svg = document.getElementById("graph");
  svg.innerHTML = "";

  // Draw edges
  for (let [u, v] of edges) {
    const p1 = positions[u];
    const p2 = positions[v];
    const isHighlighted = highlightedEdges.includes(`${u}-${v}`) || highlightedEdges.includes(`${v}-${u}`);
    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", isHighlighted ? "#3b82f6" : "#ccc");
    line.setAttribute("stroke-width", isHighlighted ? "5" : "2");
    line.setAttribute("opacity", isHighlighted ? "1" : "0.6");
    svg.appendChild(line);

    // Edge weight label with offset
    const midX = (p1.x + p2.x) / 2;
    const midY = (p1.y + p2.y) / 2;
    const dx = p2.y - p1.y;
    const dy = p1.x - p2.x;
    const len = Math.sqrt(dx * dx + dy * dy);
    const offset = 12;
    const tx = midX + (dx / len) * offset;
    const ty = midY + (dy / len) * offset;

    const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
    text.setAttribute("x", tx);
    text.setAttribute("y", ty);
    text.setAttribute("fill", "#38bdf8");
    text.setAttribute("font-size", "14");
    text.setAttribute("text-anchor", "middle");
    text.setAttribute("font-weight", "bold");
    text.textContent = graph[u][v];
    svg.appendChild(text);
  }

  // Draw nodes
  for (let i = 0; i < positions.length; i++) {
    const {x, y} = positions[i];
    const circle = document.createElementNS("http://www.w3.org/2000/svg", "circle");
    circle.setAttribute("cx", x);
    circle.setAttribute("cy", y);
    circle.setAttribute("r", 22);
    if (animPath.includes(i)) {
      circle.setAttribute("fill", "#2563eb"); // visited nodes blue
    } else if (currentNode === i) {
      circle.setAttribute("fill", "#facc15"); // current node yellow
    } else {
      circle.setAttribute("fill", "#e2e8f0"); // default nodes
    }
    circle.setAttribute("stroke", "#1e293b");
    circle.setAttribute("stroke-width", "3");
    svg.appendChild(circle);

    // Node label (number)
    const text = document.createElementNS("http://www.w3.org/2000/svg", "text");
    text.setAttribute("x", x);
    text.setAttribute("y", y + 7);
    text.setAttribute("text-anchor", "middle");
    text.setAttribute("font-size", "18");
    text.setAttribute("font-weight", "bold");
    text.setAttribute("fill", animPath.includes(i) || currentNode === i ? "#fff" : "#000");
    text.textContent = i;
    svg.appendChild(text);

    // Distance display above node if known
    if (distMap[i] !== undefined && distMap[i] !== Infinity) {
      const distText = document.createElementNS("http://www.w3.org/2000/svg", "text");
      distText.setAttribute("x", x);
      distText.setAttribute("y", y - 30);
      distText.setAttribute("text-anchor", "middle");
      distText.setAttribute("font-size", "14");
      // Final distances green, otherwise blue
      distText.setAttribute("fill", finalHighlight ? "#4ade80" : "#38bdf8");
      distText.textContent = `d: ${distMap[i]}`;
      svg.appendChild(distText);
    }
  }
}

async function runDijkstraStepByStep(start, end) {
  const dist = Array(positions.length).fill(Infinity);
  const prev = Array(positions.length).fill(null);
  const visited = Array(positions.length).fill(false);
  const pq = new PriorityQueue();
  dist[start] = 0;
  pq.enqueue(start, 0);

  animPath = [];
  distMemory = [];

  document.getElementById("explanation").innerHTML = "";

  await typeExplanation(`Starting from node ${start}. Set d[${start}] = 0. All other nodes are at infinity (∞).`);
  drawGraph([], dist, start);
  await sleep(1000);

  while (!pq.isEmpty()) {
    const u = pq.dequeue();
    if (visited[u]) continue;
    visited[u] = true;
    animPath.push(u);

    await typeExplanation(`\nExploring node ${u}.`);
    drawGraph([], dist, u);
    await sleep(800);

    for (let v = 0; v < positions.length; v++) {
      if (graph[u][v] !== Infinity && !visited[v]) {
        const alt = dist[u] + graph[u][v];
        if (alt < dist[v]) {
          await typeExplanation(`\nFound shorter path to node ${v}: updating d[${v}] from ${dist[v] === Infinity ? '∞' : dist[v]} to ${alt} via node ${u}.`);
          dist[v] = alt;
          prev[v] = u;
          pq.enqueue(v, alt);

          drawGraph([], dist, u);
          await sleep(800);
        } else {
          await typeExplanation(`\nNode ${v} already has a shorter distance d[${v}] = ${dist[v]}, so no update needed.`);
        }
      }
    }
    drawGraph([], dist, u);
    await sleep(800);
  }

  distMemory = dist.slice();

  // Show final distances in green
  drawGraph([], distMemory, null, true);

  // Build path from end to start
  const path = [];
  for (let at = end; at !== null; at = prev[at]) {
    path.push(at);
  }
  path.reverse();

  if (path[0] === start) {
    let cost = 0;
    for (let i = 1; i < path.length; i++) cost += graph[path[i - 1]][path[i]];
    document.getElementById("pathDisplay").textContent =
      `Shortest Path: ${path.join(" → ")} (Total Cost: ${cost})`;
    await animateFinalPath(path);
  } else {
    document.getElementById("pathDisplay").textContent = "No path found.";
  }
}

async function animateFinalPath(path) {
  let index = 1;
  const highlightedEdges = [];
  animPath = [path[0]];
  drawGraph(highlightedEdges, distMemory, path[0], true);

  while (index < path.length) {
    highlightedEdges.push(`${path[index - 1]}-${path[index]}`);
    animPath.push(path[index]);
    drawGraph(highlightedEdges, distMemory, path[index], true);

    await sleep(1000);
    index++;
  }
}

function fillSelects() {
  const startSel = document.getElementById("start");
  const endSel = document.getElementById("end");
  for (let i = 0; i < positions.length; i++) {
    const opt1 = document.createElement("option");
    opt1.value = i;
    opt1.textContent = i;
    const opt2 = opt1.cloneNode(true);
    startSel.appendChild(opt1);
    endSel.appendChild(opt2);
  }
  endSel.value = positions.length - 1;
}

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

  toggleBtn = document.getElementById("toggle");
  toggleBtn.onclick = () => {
    isPaused = !isPaused;
    toggleBtn.textContent = isPaused ? "Play" : "Pause";
  };

  document.getElementById("run").onclick = () => {
    if (isPaused) {
      isPaused = false;
      toggleBtn.textContent = "Pause";
    }
    animPath = [];
    document.getElementById("explanation").innerHTML = "";
    document.getElementById("pathDisplay").textContent = "Shortest Path: ";
    const start = +document.getElementById("start").value;
    const end = +document.getElementById("end").value;
    runDijkstraStepByStep(start, end);
  };

  document.getElementById("reset").onclick = () => {
    location.reload();
  };
});
</script>
</body>
</html>