451. Sort Characters By Frequency

451. Sort Characters By Frequency/451. Sort Characters By Frequency.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net8.0</TargetFramework>
+        <RootNamespace>_451._Sort_Characters_By_Frequency</RootNamespace>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

451. Sort Characters By Frequency/Program.cs

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+using _451._Sort_Characters_By_Frequency;
+
+var sol = new Solution();
+Console.WriteLine(sol.FrequencySort("gbngjaaaaaaaafsdgnjk;fdsnjkg;fds"));

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)));
+    }
+}