Merge pull request neetcode-gh#601 from KhaledSamir/khaled-topKElements

347-Top K Frequent Elements [CSharpSolution]

Author: Ahmad-A0

csharp/347-Top-K-Frequent-Elements.cs

@@ -0,0 +1,36 @@
+using System.Collections.Generic;
+using System.Linq;
+
+namespace NeetCodeCSharpSolutions.ArraysHashing
+{
+    public class Solution
+    {
+        public int[] TopKFrequent(int[] nums, int k)
+        {
+            var pq = new PriorityQueue<int, int>(new DescendingComparer());
+
+            var map = nums.GroupBy(x => x).ToDictionary(x => x.Key, x => x.Count());
+
+            foreach (var kv in map)
+            {
+                pq.Enqueue(kv.Key, kv.Value);
+            }
+
+            var ans = new List<int>();
+            while (k-- > 0)
+            {
+                ans.Add(pq.Dequeue());
+            }
+
+            return ans.ToArray();
+        }
+
+        public class DescendingComparer : IComparer<int>
+        {
+            public int Compare(int x, int y)
+            {
+                return y.CompareTo(x);
+            }
+        }
+    }
+}