Hofstadter Figure-Figure sequences: Difference between revisions

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 ( scratchpad ) 40 iota [ 1 + ffr ] map  960 iota [ 1 + ffs ] map append  1000 iota 1 v+n set= .
 t</lang>
+=={{header|FreeBASIC}}==
+{{trans|BBC-BASIC}}
+<lang freebasic>function ffr( n as integer ) as integer
+    if n = 1 then return 1
+    dim as integer i, j, r=1, s=1, v(1 to 2*n+1)
+    v(1) = 1
+    for i = 2 to n
+        for j = s to 2*n
+            if v(j) = 0 then exit for
+        next j
+        v(j) = 1
+        s = j
+        r += s
+        if r <= 2*n then v(r) = 1
+    next i
+    return r
+end function
+function ffs( n as integer ) as integer
+    if n = 1 then return 2
+    dim as integer i, j, r=1, s=2, v(1 to 2*n+1)
+    for i = 1 to n
+        for j = s to 2*n
+            if v(j) = 0 then exit for
+        next j
+        v(j) = 1
+        s = j
+        r += s
+        if r <= 2*n then v(r) = 1
+    next i
+    return s
+end function
+dim as integer i
+print " R"," S"
+print
+for i = 1 to 10
+    print ffr(i), ffs(i)
+next i
+dim as boolean found(1 to 1000), failed
+for i = 1 to 40
+    found(ffr(i)) = true
+next i
+for i = 1 to 960
+    found(ffs(i)) = true
+next i
+for i = 1 to 1000
+    if found(i) = false then failed = true
+next i
+if failed then print "Oh no!" else print "All integers from 1 to 1000 accounted for"</lang>
+{{out}}<pre>
+ R             S
+2
+4
+5
+6
+8
+9
+10
+11
+13
+14
+All integers from 1 to 1000 accounted for
+</pre>
 =={{header|Go}}==