Data update

Task/Floyd-Warshall-algorithm/Dart/floyd-warshall-algorithm.dart

@@ -0,0 +1,54 @@
+void main() {
+  List<List<int>> weights = [
+    [1, 3, -2],
+    [2, 1, 4],
+    [2, 3, 3],
+    [3, 4, 2],
+    [4, 2, -1]
+  ];
+  int numVertices = 4;
+  floydWarshall(weights, numVertices);
+}
+
+void floydWarshall(List<List<int>> weights, int numVertices) {
+  List<List<double>> dist = List.generate(
+      numVertices, (_) => List.filled(numVertices, double.infinity));
+
+  for (var w in weights) {
+    dist[w[0] - 1][w[1] - 1] = w[2].toDouble();
+  }
+
+  List<List<int>> next = List.generate(
+      numVertices, (i) => List.generate(numVertices, (j) => j != i ? j + 1 : 0));
+
+  for (int k = 0; k < numVertices; k++) {
+    for (int i = 0; i < numVertices; i++) {
+      for (int j = 0; j < numVertices; j++) {
+        if (dist[i][k] + dist[k][j] < dist[i][j]) {
+          dist[i][j] = dist[i][k] + dist[k][j];
+          next[i][j] = next[i][k];
+        }
+      }
+    }
+  }
+
+  printResult(dist, next);
+}
+
+void printResult(List<List<double>> dist, List<List<int>> next) {
+  print("pair     dist    path");
+  for (int i = 0; i < next.length; i++) {
+    for (int j = 0; j < next.length; j++) {
+      if (i != j) {
+        int u = i + 1;
+        int v = j + 1;
+        String path = "$u -> $v    ${dist[i][j].toInt()}     $u";
+        do {
+          u = next[u - 1][v - 1];
+          path += " -> $u";
+        } while (u != v);
+        print(path);
+      }
+    }
+  }
+}