451. Sort Characters By Frequency

451. Sort Characters By Frequency/Solution.cs

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+namespace _451._Sort_Characters_By_Frequency;
+
+public class Solution
+{
+    public string FrequencySort(string s)
+    {
+        Dictionary<char, int> dictionary = [];
+        foreach (var c in s.Where(c => !dictionary.TryAdd(c, 1)))
+            dictionary[c]++;
+
+        var list = dictionary.ToList();
+        return String.Join("",
+            list.OrderByDescending(element => element.Value)
+                .Select(element => new string(element.Key, element.Value)));
+    }
+}