September 2017 Update

Task/Move-to-front-algorithm/Phix/move-to-front-algorithm.phix

@@ -0,0 +1,38 @@
+function encode(string s)
+    string symtab = "abcdefghijklmnopqrstuvwxyz"
+    sequence res = {}
+    for i=1 to length(s) do
+        integer ch = s[i]
+        integer k = find(ch,symtab)
+        res &= k-1
+        for j=k to 2 by -1 do
+            symtab[j] = symtab[j-1]
+        end for
+        symtab[1] = ch
+    end for
+    return res
+end function
+
+function decode(sequence s)
+    string symtab = "abcdefghijklmnopqrstuvwxyz"
+    string res = ""
+    for i=1 to length(s) do
+        integer k = s[i]+1
+        integer ch = symtab[k]
+        res &= ch
+        for j=k to 2 by -1 do
+            symtab[j] = symtab[j-1]
+        end for
+        symtab[1] = ch
+    end for
+    return res
+end function
+
+procedure test(string s)
+    sequence e = encode(s)
+    string d = decode(e)
+    ?{s,e,d,{"**ERROR**","ok"}[(s=d)+1]}
+end procedure
+test("broood")
+test("bananaaa")
+test("hiphophiphop")