HackerRankAnagram.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        string a = Console.ReadLine();
           string b = Console.ReadLine();

            a = String.Concat(a.OrderBy(c => c));
            b = String.Concat(b.OrderBy(c => c));

            if(a == b)
            {
                Console.WriteLine(0);
            }

            var dica = a.GroupBy(x => x).ToDictionary(x => x.Key, g => g.Count());
            var dicb = b.GroupBy(x => x).ToDictionary(x => x.Key, g => g.Count());
           
            var sum = 0;
            var diffa = dica.Except(dicb).ToDictionary(s => s.Key, s=>s.Value);
            var diffb = dicb.Except(dica).ToDictionary(s => s.Key, s=>s.Value);

            foreach(var apair in diffa)
            {
                if(diffb.ContainsKey(apair.Key))
                {
                    sum += Math.Abs(apair.Value-diffb[apair.Key]);
                    diffb.Remove(apair.Key);
                }
                else
                {
                    sum += apair.Value;
                }
            }

            sum += diffb.Sum(x => x.Value);

            Console.WriteLine(sum);
        
    }
}