Data update

Task/Floyd-Warshall-algorithm/R/floyd-warshall-algorithm.r

@@ -0,0 +1,67 @@
+floydWarshall <- function(weights, numVertices) {
+  # Initialize distance matrix with infinity
+  dist <- matrix(Inf, nrow = numVertices, ncol = numVertices)
+
+  # Set diagonal elements to zero
+  diag(dist) <- 0
+
+  # Fill the distance matrix with the given weights
+  for (i in 1:nrow(weights)) {
+    dist[weights[i, 1], weights[i, 2]] <- weights[i, 3]
+  }
+
+  # Initialize nextNode matrix
+  nextNode <- matrix(0, nrow = numVertices, ncol = numVertices)
+  for (i in 1:numVertices) {
+    for (j in 1:numVertices) {
+      if (i != j) {
+        nextNode[i, j] <- j
+      }
+    }
+  }
+
+  # Floyd-Warshall algorithm
+  for (k in 1:numVertices) {
+    for (i in 1:numVertices) {
+      for (j in 1:numVertices) {
+        if (dist[i, k] + dist[k, j] < dist[i, j]) {
+          dist[i, j] <- dist[i, k] + dist[k, j]
+          nextNode[i, j] <- nextNode[i, k]
+        }
+      }
+    }
+  }
+
+  printResult(dist, nextNode)
+}
+
+printResult <- function(dist, nextNode) {
+  cat("pair dist path\n")
+  for (i in 1:nrow(nextNode)) {
+    for (j in 1:ncol(nextNode)) {
+      if (i != j) {
+        u <- i
+        v <- j
+        path <- sprintf("%d -> %d %2d %s", i, j, dist[i, j], i)
+        repeat {
+          u <- nextNode[u, v]
+          path <- paste(path, "->", u)
+          if (u == v) break
+        }
+        cat(path, "\n")
+      }
+    }
+  }
+}
+
+# Example usage
+weights <- matrix(c(
+  1, 3, -2,
+  2, 1, 4,
+  2, 3, 3,
+  3, 4, 2,
+  4, 2, -1
+), ncol = 3, byrow = TRUE)
+
+numVertices <- 4
+floydWarshall(weights, numVertices)