Data commit

Task/Hofstadter-Q-sequence/ERRE/hofstadter-q-sequence.erre

@@ -0,0 +1,35 @@
+PROGRAM HOFSTADER_Q
+
+!
+! for rosettacode.org
+!
+
+DIM Q%[10000]
+
+PROCEDURE QSEQUENCE(Q,FLAG%->SEQ$)
+! if FLAG% is true accumulate sequence in SEQ$
+! (attention to string var lenght=255)
+! otherwise calculate values in Q%[] only
+
+  LOCAL N
+  Q%[1]=1
+  Q%[2]=1
+  SEQ$="1 1"
+  IF NOT FLAG% THEN Q=NUM END IF
+  FOR N=3 TO Q DO
+    Q%[N]=Q%[N-Q%[N-1]]+Q%[N-Q%[N-2]]
+    IF FLAG% THEN SEQ$=SEQ$+STR$(Q%[N]) END IF
+  END FOR
+END PROCEDURE
+
+BEGIN
+  NUM=10000
+  QSEQUENCE(10,TRUE->SEQ$)
+  PRINT("Q-sequence(1..10) : ";SEQ$)
+  QSEQUENCE(1000,FALSE->SEQ$)
+  PRINT("1000th number of Q sequence : ";Q%[1000])
+  FOR N=2 TO NUM DO
+    IF Q%[N]<Q%[N-1] THEN NN+=1 END IF
+  END FOR
+  PRINT("Number of Q(n)<Q(n+1) for n<=10000 : ";NN)
+END PROGRAM