Initial data commit

Task/Recamans-sequence/Python/recamans-sequence-2.py

@@ -0,0 +1,67 @@
+'''Recaman sequence'''
+
+
+# recamanUntil :: (Int -> Set Int > [Int] -> Bool) -> [Int]
+def recamanUntil(p):
+    '''All terms of the Recaman series before the
+       first term for which the predicate p holds.'''
+    n = 1
+    r = 0  # First term of series
+    rs = [r]
+    seen = set(rs)
+    blnNew = True
+    while not p(seen, n, r, blnNew):
+        r = recamanSucc(seen, n, r)
+        blnNew = r not in seen
+        seen.add(r)
+        rs.append(r)
+        n = 1 + n
+    return rs
+
+
+# recamanSucc :: Set Int -> Int -> Int
+def recamanSucc(seen, n, r):
+    '''The successor for a given Recaman term,
+       given the set of Recaman terms seen so far.'''
+    back = r - n
+    return n + r if 0 > back or (back in seen) else back
+
+
+# ------------------------- TEST -------------------------
+# main :: IO ()
+def main():
+    '''Test'''
+    print(
+        'First 15 Recaman:\r',
+        recamanUntil(
+            lambda seen, n, r, _: 15 == n
+        )
+    )
+    print(
+        'First duplicated Recaman:\r',
+        recamanUntil(
+            lambda seen, n, r, blnNew: not blnNew
+        )[-1]
+    )
+    setK = set(enumFromTo(0)(1000))
+    print(
+        'Number of Recaman terms needed to generate',
+        'all integers from [0..1000]:\r',
+        len(recamanUntil(
+            lambda seen, n, r, blnNew: (
+                blnNew and 1001 > r and setK.issubset(seen)
+            )
+        )) - 1
+    )
+
+
+# ----------------------- GENERIC ------------------------
+
+# enumFromTo :: (Int, Int) -> [Int]
+def enumFromTo(m):
+    '''Integer enumeration from m to n.'''
+    return lambda n: range(m, 1 + n)
+
+
+if __name__ == '__main__':
+    main()