Data commit

Task/Smith-numbers/C-sharp/smith-numbers.cs

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+using System;
+using System.Collections.Generic;
+
+namespace SmithNumbers {
+    class Program {
+        static int SumDigits(int n) {
+            int sum = 0;
+            while (n > 0) {
+                n = Math.DivRem(n, 10, out int rem);
+                sum += rem;
+            }
+            return sum;
+        }
+
+        static List<int> PrimeFactors(int n) {
+            List<int> result = new List<int>();
+
+            for (int i = 2; n % i == 0; n /= i) {
+                result.Add(i);
+            }
+
+            for (int i = 3; i * i < n; i += 2) {
+                while (n % i == 0) {
+                    result.Add(i);
+                    n /= i;
+                }
+            }
+
+            if (n != 1) {
+                result.Add(n);
+            }
+
+            return result;
+        }
+
+        static void Main(string[] args) {
+            const int SIZE = 8;
+            int count = 0;
+            for (int n = 1; n < 10_000; n++) {
+                var factors = PrimeFactors(n);
+                if (factors.Count > 1) {
+                    int sum = SumDigits(n);
+                    foreach (var f in factors) {
+                        sum -= SumDigits(f);
+                    }
+                    if (sum == 0) {
+                        Console.Write("{0,5}", n);
+                        if (count == SIZE - 1) {
+                            Console.WriteLine();
+                        }
+                        count = (count + 1) % SIZE;
+                    }
+                }
+            }
+        }
+    }
+}