bellman-ford

Author: akash205sharma

src/algorithms/graph/bellmanFord.js

@@ -7,31 +7,49 @@ export default function runBellmanFord(nodes, edges, source) {
 
   // Relax edges |V|-1 times
   for (let i = 0; i < nodes.length - 1; i++) {
+    let updated = false;
     for (const edge of edges) {
-      const { from, to, weight } = edge;
+      const from = edge.u ?? edge.from;
+      const to = edge.v ?? edge.to;
+      const weight = edge.w ?? edge.weight;
+
       const step = {
         type: "relax",
         iteration: i + 1,
-        edge,
-        prevDistance: dist[to]
+        edge: { u: from, v: to, w: weight },
+        prevDistance: dist[to],
       };
 
-      if (dist[from] + weight < dist[to]) {
+      // ✅ Important: Check dist[from] !== Infinity before relaxing
+      if (dist[from] !== Infinity && dist[from] + weight < dist[to]) {
         dist[to] = dist[from] + weight;
         step.updatedDistance = dist[to];
+        updated = true;
+      } else {
+        step.type = "skip";
       }
 
       steps.push(step);
     }
+
+    // Optimization: if no update in this pass, break early
+    if (!updated) break;
   }
 
   // Check for negative weight cycles
   for (const edge of edges) {
-    const { from, to, weight } = edge;
-    if (dist[from] + weight < dist[to]) {
-      steps.push({ type: "negativeCycle", edge });
+    const from = edge.u ?? edge.from;
+    const to = edge.v ?? edge.to;
+    const weight = edge.w ?? edge.weight;
+
+    if (dist[from] !== Infinity && dist[from] + weight < dist[to]) {
+      steps.push({ type: "negative-cycle", edge: { u: from, v: to, w: weight } });
     }
   }
 
-  return steps;
+  // Push final state step for visualization
+  steps.push({ type: "done", distances: { ...dist } });
+
+  // Return both steps & final distances
+  return { steps, distances: dist };
 }