Data update

Task/Move-to-front-algorithm/SETL/move-to-front-algorithm.setl

@@ -0,0 +1,31 @@
+program move_to_front;
+    tests := ["broood", "bananaaa", "hiphophiphop"];
+    alph := "abcdefghijklmnopqrstuvwxyz";
+
+    loop for test in tests do
+        e := encode(test, alph);
+        d := decode(e, alph);
+        v := if test = d then "(ok)" else "(fail)" end;
+        print(test,"->",e,"->",d,v);
+    end loop;
+
+    proc encode(s, alph);
+        enc := [];
+        loop for c in s do
+            [i, j] := mark(alph, c);
+            alph := c + alph(..i-1) + alph(j+1..);
+            enc with:= i-1;
+        end loop;
+        return enc;
+    end proc;
+
+    proc decode(ls, alph);
+        s := "";
+        loop for i in ls do
+            c := alph(i + 1);
+            s +:= c;
+            alph := c + alph(..i) + alph(i+2..);
+        end loop;
+        return s;
+    end proc;
+end program;