Dijkstra's Algorithm

1function dijkstra(graph, startNode) {
2  const distances = {};
3  const visited = new Set();
4  
5  // Simple Min-Priority Queue helper
6  for (const node in graph) {
7    distances[node] = Infinity;
8  }
9  distances[startNode] = 0;
10 
11  const pq = [[0, startNode]]; // [distance, node]
12 
13  while (pq.length > 0) {
14    // Sort to extract minimum (Min-Heap simulation)
15    pq.sort((a, b) => a[0] - b[0]);
16    const [currDist, u] = pq.shift();
17 
18    if (visited.has(u)) continue;
19    visited.add(u);
20 
21    for (const neighbor in graph[u]) {
22      const weight = graph[u][neighbor];
23      const alt = currDist + weight;
24 
25      if (alt < distances[neighbor]) {
26        distances[neighbor] = alt;
27        pq.push([alt, neighbor]);
28      }
29    }
30  }
31 
32  return distances;
33}
34 
35// Example graph:
36// const graph = {
37//   A: { B: 4, C: 2 },
38//   B: { C: 1, D: 5 },
39//   C: { B: 1, D: 8, E: 10 },
40//   D: { E: 2 },
41//   E: {}
42// };
43// dijkstra(graph, 'A'); // { A: 0, B: 3, C: 2, D: 8, E: 10 }