Day5

409. Longest Palindrome/409. Longest Palindrome.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>_409._Longest_Palindrome</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

409. Longest Palindrome/Program.cs

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+namespace _409._Longest_Palindrome
+{
+    internal class Program
+    {
+        static void Main(string[] args)
+        {
+            Console.WriteLine(new Solution().LongestPalindrome("bb"));
+        }
+    }
+}

409. Longest Palindrome/Solution.cs

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+namespace _409._Longest_Palindrome;
+
+public class Solution
+{
+    public int LongestPalindrome(string s)
+    {
+        Dictionary<char, int> dict = new Dictionary<char, int>();
+        foreach(var ch in s)
+        {
+            if(dict.ContainsKey(ch))
+                dict[ch]++;
+            else
+                dict.Add(ch, 1);
+        }
+        int sum = 0;
+        bool hasOdd = false;
+        foreach(var v in dict.Values)
+        {
+            sum += v / 2;
+            if(v % 2 == 1)
+                hasOdd = true;
+        }
+        return sum*2 + (hasOdd ? 1 : 0);
+    }
+}