implemented floydwarshall visualizer

Author: tusharpatel0504

src/algorithms/graph/floydWarshall.js

@@ -0,0 +1,123 @@
+// src/algorithms/graph/floydWarshall.js
+
+// 🧠 Generator that yields every visualization step
+export function* floydWarshallSteps(edges, nodeCount) {
+  // Initialize distance matrix with Infinity
+  const dist = Array.from({ length: nodeCount }, () =>
+    Array(nodeCount).fill(Infinity)
+  );
+
+  // Distance from a node to itself is 0
+  for (let i = 0; i < nodeCount; i++) {
+    dist[i][i] = 0;
+  }
+
+  // Set initial distances from edges (use minimum weight for each pair)
+  for (let edge of edges) {
+    const from = edge.from - 1;
+    const to = edge.to - 1;
+    if (edge.weight < dist[from][to]) {
+      dist[from][to] = edge.weight;
+    }
+    // For undirected graphs, uncomment the next line
+    // if (edge.weight < dist[to][from]) dist[to][from] = edge.weight;
+  }
+
+  yield {
+    type: "init",
+    dist: dist.map((row) => [...row]),
+    message: "Initial distance matrix created",
+  };
+
+  // Floyd-Warshall algorithm
+  for (let k = 0; k < nodeCount; k++) {
+    yield {
+      type: "intermediate",
+      k,
+      dist: dist.map((row) => [...row]),
+      message: `Using node ${k + 1} as intermediate`,
+    };
+
+    for (let i = 0; i < nodeCount; i++) {
+      for (let j = 0; j < nodeCount; j++) {
+        if (i === j) continue;
+
+        const oldDist = dist[i][j];
+        const newDist = dist[i][k] + dist[k][j];
+
+        if (newDist < oldDist) {
+          dist[i][j] = newDist;
+          yield {
+            type: "update",
+            k,
+            i,
+            j,
+            oldDist,
+            newDist,
+            dist: dist.map((row) => [...row]),
+            message: `Updated dist[${i + 1}][${j + 1}] from ${
+              oldDist === Infinity ? "∞" : oldDist
+            } to ${newDist}`,
+          };
+        } else {
+          yield {
+            type: "compare",
+            k,
+            i,
+            j,
+            oldDist,
+            newDist,
+            dist: dist.map((row) => [...row]),
+            message: `No update: dist[${i + 1}][${j + 1}] = ${
+              oldDist === Infinity ? "∞" : oldDist
+            } ≤ ${newDist === Infinity ? "∞" : newDist}`,
+          };
+        }
+      }
+    }
+  }
+
+  // Check for negative cycles
+  let hasNegativeCycle = false;
+  for (let i = 0; i < nodeCount; i++) {
+    if (dist[i][i] < 0) {
+      hasNegativeCycle = true;
+      break;
+    }
+  }
+
+  yield {
+    type: "done",
+    dist: dist.map((row) => [...row]),
+    hasNegativeCycle,
+    message: hasNegativeCycle
+      ? "Algorithm complete - Negative cycle detected!"
+      : "Algorithm complete - All shortest paths found",
+  };
+}
+
+// Helper function to get shortest path between two nodes
+export function getShortestPath(dist, predecessor, start, end) {
+  if (dist[start][end] === Infinity) {
+    return null; // No path exists
+  }
+
+  const path = [];
+  let current = start;
+  path.push(current);
+
+  while (current !== end) {
+    current = predecessor[current][end];
+    if (current === undefined || current === null) break;
+    path.push(current);
+  }
+
+  return path.length > 1 && path[path.length - 1] === end ? path : null;
+}
+
+// Helper function to format distance matrix for display
+export function formatDistanceMatrix(dist) {
+  return dist.map((row) =>
+    row.map((val) => (val === Infinity ? "∞" : val.toString()))
+  );
+}