Data commit

Task/Kolakoski-sequence/Python/kolakoski-sequence.py

@@ -0,0 +1,35 @@
+import itertools
+
+def cycler(start_items):
+	return itertools.cycle(start_items).__next__
+
+def _kolakoski_gen(start_items):
+    s, k = [], 0
+    c = cycler(start_items)
+    while True:
+        c_next = c()
+        s.append(c_next)
+        sk = s[k]
+        yield sk
+        if sk > 1:
+            s += [c_next] * (sk - 1)
+        k += 1
+
+def kolakoski(start_items=(1, 2), length=20):
+    return list(itertools.islice(_kolakoski_gen(start_items), length))
+
+def _run_len_encoding(truncated_series):
+    return [len(list(group)) for grouper, group in itertools.groupby(truncated_series)][:-1]
+
+def is_series_eq_its_rle(series):
+    rle = _run_len_encoding(series)
+    return (series[:len(rle)] == rle) if rle else not series
+
+if __name__ == '__main__':
+    for start_items, length in [((1, 2), 20), ((2, 1), 20),
+                                ((1, 3, 1, 2), 30), ((1, 3, 2, 1), 30)]:
+        print(f'\n## {length} members of the series generated from {start_items} is:')
+        s = kolakoski(start_items, length)
+        print(f'  {s}')
+        ans = 'YES' if is_series_eq_its_rle(s) else 'NO'
+        print(f'  Does it look like a Kolakoski sequence: {ans}')