Merge pull request AllAlgorithms#18 from NerdyPepper/master

abranhe · web-flow · commit 71ad34ad14e1 · 2018-10-03T01:53:05.000-04:00
Add ducci sequence program
diff --git a/math/ducci.py b/math/ducci.py
@@ -0,0 +1,15 @@
+def ducci_sequence(*ns):
+    while True:
+        yield ns
+        ns = tuple(abs(ns[i - 1] - ns[i]) for i in range(len(ns)))
+
+def ducci(*ns):
+    known = set()
+    for ns in ducci_sequence(*ns):
+        print(ns)
+        if ns in known or set(ns) == {0}:
+            break
+        known.add(ns)
+    return len(known) + 1
+
+print(ducci(0, 653, 1854, 4063), "steps")
