Data commit

Task/Casting-out-nines/C-sharp/casting-out-nines.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace CastingOutNines {
+    public static class Helper {
+        public static string AsString<T>(this IEnumerable<T> e) {
+            var it = e.GetEnumerator();
+
+            StringBuilder builder = new StringBuilder();
+            builder.Append("[");
+
+            if (it.MoveNext()) {
+                builder.Append(it.Current);
+            }
+            while (it.MoveNext()) {
+                builder.Append(", ");
+                builder.Append(it.Current);
+            }
+
+            builder.Append("]");
+            return builder.ToString();
+        }
+    }
+
+    class Program {
+        static List<int> CastOut(int @base, int start, int end) {
+            int[] ran = Enumerable
+                .Range(0, @base - 1)
+                .Where(a => a % (@base - 1) == (a * a) % (@base - 1))
+                .ToArray();
+            int x = start / (@base - 1);
+
+            List<int> result = new List<int>();
+            while (true) {
+                foreach (int n in ran) {
+                    int k = (@base - 1) * x + n;
+                    if (k < start) {
+                        continue;
+                    }
+                    if (k > end) {
+                        return result;
+                    }
+                    result.Add(k);
+                }
+                x++;
+            }
+        }
+
+        static void Main() {
+            Console.WriteLine(CastOut(16, 1, 255).AsString());
+            Console.WriteLine(CastOut(10, 1, 99).AsString());
+            Console.WriteLine(CastOut(17, 1, 288).AsString());
+        }
+    }
+}