Data commit

Task/Hofstadter-Q-sequence/Seed7/hofstadter-q-sequence.seed7

@@ -0,0 +1,38 @@
+$ include "seed7_05.s7i";
+
+const type: intHash is hash [integer] integer;
+
+var intHash: qHash is intHash.value;
+
+const func integer: q (in integer: n) is func
+  result
+    var integer: q is 1;
+  begin
+    if n in qHash then
+      q := qHash[n];
+    else
+      if n > 2 then
+        q := q(n - q(pred(n))) + q(n - q(n - 2));
+      end if;
+      qHash @:= [n] q;
+    end if;
+  end func;
+
+const proc: main is func
+  local
+    var integer: n is 0;
+    var integer: less_than_preceding is 0;
+  begin
+    writeln("q(n) for n = 1 .. 10:");
+    for n range 1 to 10 do
+      write(q(n) <& " ");
+    end for;
+    writeln;
+    writeln("q(1000)=" <& q(1000));
+    for n range 2 to 100000 do
+      if q(n) < q(pred(n)) then
+        incr(less_than_preceding);
+      end if;
+    end for;
+    writeln("q(n) < q(n-1) for n = 2 .. 100000: " <& less_than_preceding);
+  end func;