Data commit

Task/Floyd-Warshall-algorithm/Lua/floyd-warshall-algorithm.lua

@@ -0,0 +1,65 @@
+function printResult(dist, nxt)
+    print("pair     dist    path")
+    for i=0, #nxt do
+        for j=0, #nxt do
+            if i ~= j then
+                u = i + 1
+                v = j + 1
+                path = string.format("%d -> %d    %2d     %s", u, v, dist[i][j], u)
+                repeat
+                    u = nxt[u-1][v-1]
+                    path = path .. " -> " .. u
+                until (u == v)
+                print(path)
+            end
+        end
+    end
+end
+
+function floydWarshall(weights, numVertices)
+    dist = {}
+    for i=0, numVertices-1 do
+        dist[i] = {}
+        for j=0, numVertices-1 do
+            dist[i][j] = math.huge
+        end
+    end
+
+    for _,w in pairs(weights) do
+        -- the weights array is one based
+        dist[w[1]-1][w[2]-1] = w[3]
+    end
+
+    nxt = {}
+    for i=0, numVertices-1 do
+        nxt[i] = {}
+        for j=0, numVertices-1 do
+            if i ~= j then
+                nxt[i][j] = j+1
+            end
+        end
+    end
+
+    for k=0, numVertices-1 do
+        for i=0, numVertices-1 do
+            for j=0, numVertices-1 do
+                if dist[i][k] + dist[k][j] < dist[i][j] then
+                    dist[i][j] = dist[i][k] + dist[k][j]
+                    nxt[i][j] = nxt[i][k]
+                end
+            end
+        end
+    end
+
+    printResult(dist, nxt)
+end
+
+weights = {
+    {1, 3, -2},
+    {2, 1, 4},
+    {2, 3, 3},
+    {3, 4, 2},
+    {4, 2, -1}
+}
+numVertices = 4
+floydWarshall(weights, numVertices)