Data update

Task/Digital-root/Crystal/digital-root-2.cr

@@ -0,0 +1,18 @@
+def digital_root_with_persistence(n : Int) : {Int32, Int32}
+  n = n.abs
+  persistence = 0
+
+  until n <= 9
+    persistence += 1
+
+    digit_sum = (0..(Math.log10(n).floor.to_i)).sum { |i| (n % 10**(i + 1) - n % 10**i) // 10**i }
+
+    n = digit_sum
+  end
+
+  {n, persistence}
+end
+
+puts digital_root_with_persistence 627615
+puts digital_root_with_persistence 39390
+puts digital_root_with_persistence 588225