Data update

Task/Move-to-front-algorithm/Pluto/move-to-front-algorithm.pluto

@@ -0,0 +1,53 @@
+local fmt = require "fmt"
+require "table2"
+
+local function encode(s)
+    if s == "" then return {} end
+    local symbols = "abcdefghijklmnopqrstuvwxyz":split("")
+    local result = table.rep(#s, 0)
+    for i = 1, #s do
+        local c = s[i]
+        local index = symbols:findindex(|ch| -> ch == c)
+        if !index then error($"{s} contains a non-alphabetic character") end
+        result[i] = index
+        if index > 1 then
+            for k = index - 1, 1, -1 do symbols[k + 1] = symbols[k] end
+            symbols[1] = c
+        end
+    end
+    return result
+end
+
+local function decode(a)
+    if #a == 0 then return "" end
+    local symbols = "abcdefghijklmnopqrstuvwxyz":split("")
+    local result = table.rep(#a, "")
+    local i = 1
+    for a as n do
+        if n < 1 or n > 26 then error($"{fmt.format("%,s", a)} contains an invalid number") end
+        result[i] = symbols[n]
+        if n > 1  then
+            for j = n - 1, 1, -1 do symbols[j + 1] = symbols[j] end
+            symbols[1] = result[i]
+        end
+        i += 1
+    end
+    return result:concat("")
+end
+
+local strings = {"broood", "bananaaa", "hiphophiphop"}
+local encoded = table.create(#strings)
+
+for i, s in strings do
+    encoded[i] = encode(s)
+    fmt.print("%-12s -> %,s", s, encoded[i])
+end
+print()
+local decoded = table.create(#encoded)
+i = 1
+for encoded as a do
+    decoded[i] = decode(a)
+    local correct = (decoded[i] == strings[i]) ? "correct" : "incorrect"
+    fmt.print("%,-38s -> %-12s -> %s", a, decoded[i], correct)
+    i += 1
+end