Data commit

Task/Calkin-Wilf-sequence/Python/calkin-wilf-sequence.py

@@ -0,0 +1,31 @@
+from fractions import Fraction
+from math import floor
+from itertools import islice, groupby
+
+
+def cw():
+    a = Fraction(1)
+    while True:
+        yield a
+        a = 1 / (2 * floor(a) + 1 - a)
+
+def r2cf(rational):
+    num, den = rational.numerator, rational.denominator
+    while den:
+        num, (digit, den) = den, divmod(num, den)
+        yield digit
+
+def get_term_num(rational):
+    ans, dig, pwr = 0, 1, 0
+    for n in r2cf(rational):
+        for _ in range(n):
+            ans |= dig << pwr
+            pwr += 1
+        dig ^= 1
+    return ans
+
+
+if __name__ == '__main__':
+    print('TERMS 1..20: ', ', '.join(str(x) for x in islice(cw(), 20)))
+    x = Fraction(83116, 51639)
+    print(f"\n{x} is the {get_term_num(x):_}'th term.")