Data update

Task/Floyd-Warshall-algorithm/Julia/floyd-warshall-algorithm.jl

@@ -0,0 +1,38 @@
+# Floyd-Warshall algorithm: https://rosettacode.org/wiki/Floyd-Warshall_algorithm
+# v0.6
+
+function floydwarshall(weights::Matrix, nvert::Int)
+    dist = fill(Inf, nvert, nvert)
+    for i in 1:size(weights, 1)
+        dist[weights[i, 1], weights[i, 2]] = weights[i, 3]
+    end
+    # return dist
+    next = collect(j != i ? j : 0 for i in 1:nvert, j in 1:nvert)
+
+    for k in 1:nvert, i in 1:nvert, j in 1:nvert
+        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]
+        end
+    end
+
+    # return next
+    function printresult(dist, next)
+        println("pair     dist    path")
+        for i in 1:size(next, 1), j in 1:size(next, 2)
+            if i != j
+                u = i
+                path = @sprintf "%d -> %d    %2d     %s" i j dist[i, j] i
+                while true
+                    u = next[u, j]
+                    path *= " -> $u"
+                    if u == j break end
+                end
+                println(path)
+            end
+        end
+    end
+    printresult(dist, next)
+end
+
+floydwarshall([1 3 -2; 2 1 4; 2 3 3; 3 4 2; 4 2 -1], 4)