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CollectionUtils.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq; 
+using System.Text;
+
+namespace First_week
+{
+    internal static class CollectionUtils
+    {
+        public static bool IsNullOrEmpty<T>(this IEnumerable<T> collection)
+        {
+            return collection == null || !collection.Any();
+        }
+        public static List<T> ToSafeList<T>(this IEnumerable<T> collection)
+        {
+            return collection?.ToList() ?? new List<T>();
+        }
+
+        public static void Shuffle<T>(this IList<T> list)
+        {
+            if (list == null)
+                return;
+
+            Random rng = new Random();
+            int n = list.Count;
+            while (n > 1)
+            {
+                n--;
+                int k = rng.Next(n + 1);
+                T value = list[k];
+                list[k] = list[n];
+                list[n] = value;
+            }
+        }
+    }
+}