Just another update

Task/Permutations/Lua/permutations-2.lua

@@ -0,0 +1,31 @@
+-- Iterative version
+function ipermutations(a,b)
+    if a==0 then return end
+    local taken = {} local slots = {}
+    for i=1,a do slots[i]=0 end
+    for i=1,b do taken[i]=false end
+    local index = 1
+    while index > 0 do repeat
+        repeat slots[index] = slots[index] + 1
+        until slots[index] > b or not taken[slots[index]]
+        if slots[index] > b then
+            slots[index] = 0
+            index = index - 1
+            if index > 0 then
+                taken[slots[index]] = false
+            end
+            break
+        else
+            taken[slots[index]] = true
+        end
+        if index == a then
+            for i=1,a do io.write(slots[i]) io.write(" ") end
+            io.write("\n")
+            taken[slots[index]] = false
+            break
+        end
+        index = index + 1
+    until true end
+end
+
+ipermutations(3, 3)