Data update

Task/Floyd-Warshall-algorithm/Pluto/floyd-warshall-algorithm.pluto

@@ -0,0 +1,51 @@
+require "table2"
+require "math2"
+
+class floydWarshall
+    static function do_calcs(weights, nvertices)
+        local dist = {}
+        local next = {}
+        for i = 1, nvertices do
+            dist[i] = table.rep(nvertices, 1/0)
+            next[i] = table.rep(nvertices, 1)
+            for j = 1, nvertices do
+                if i != j then next[i][j] = j end
+            end
+        end
+        for weights as w do dist[w[1]][w[2]] = w[3] end
+        for k = 1, nvertices do
+            for i = 1, nvertices do
+                for j = 1, nvertices do
+                    if (dist[i][k] + dist[k][j] < dist[i][j]) then
+                        dist[i][j] = dist[i][k] + dist[k][j]
+                        next[i][j] = next[i][k]
+                    end
+                end
+            end
+        end
+        floydWarshall.print_result(dist, next)
+    end
+
+    static function print_result(dist, next)
+        print("pair     dist    path")
+        for i = 1, #next do
+            for j = 1, #next do
+                if i != j then
+                    local u = i
+                    local v = j
+                    local path = string.format("%d -> %d    %2d     %s", u, v, math.trunc(dist[i][j]), u)
+                    while true do
+                        u = next[u][v]
+                        path ..=  " -> " .. u
+                        if u == v then break end
+                    end
+                    print(path)
+                end
+            end
+        end
+    end
+end
+
+local weights = { {1, 3, -2}, {2, 1, 4}, {2, 3, 3}, {3, 4, 2}, {4, 2, -1} }
+local nvertices = 4
+floydWarshall.do_calcs(weights, nvertices)