Odd Occurrences in Array - Codibility - C#

OddOccurrencesInArray.cs

using System;
using System.Collections.Generic;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] example = { 0, 0, 1, 2, 2, 3, 3, 0, 0, 2, 2, 2, 3, 3, 1, 8 };

            var S = new Solution(); 
            Console.WriteLine($"Our Odd Val was {S.solution(example)}");
        }
    }

    class Solution
    {
        public int solution(int[] A)
        {
            var dictionary = new Dictionary<int, short>();
            int? oddVal = null;

            for (var i = 0; i < A.Length; i++)
            {
                if (dictionary.ContainsKey(A[i]))
                {
                    dictionary[A[i]] = 2;
                } else
                {
                    dictionary.Add(A[i], 1);
                }
            }

            foreach (KeyValuePair<int, short> entry in dictionary)
            {
                if (entry.Value == 1)
                {
                    oddVal = entry.Key;
                    break;
                }
            }

            return (int)oddVal;
        }
    }
}

This code fails some of the performance test and sum up upto 66% correctness only.

This code fails some of the performance test and sum up upto 66% correctness only.

Facing the same.

using System;
using System.Linq;

class Solution {
public int solution(int[] A) {
var output = A.GroupBy(x => x)
.Select(g => new {Value = g.Key, Count = g.Count()})
.Where(x=>x.Count % 2 == 1)?.FirstOrDefault()?.Value;

    return output ?? 0;
}

}

A lot of this code is from writing (poor) implementations for the first time in C#. By no means should anyone use it for any purpose (it totally sucks).

using System; using System.Linq;

class Solution { public int solution(int[] A) { var output = A.GroupBy(x => x) .Select(g => new {Value = g.Key, Count = g.Count()}) .Where(x=>x.Count % 2 == 1)?.FirstOrDefault()?.Value;

    return output ?? 0;
}

}

This answer is awesome

This is another simplified solution, that does not handle if there is no "alone" element.

using System;
using System.Linq;

class Solution {
  public int solution(int[] A)
  {
    var result = A.GroupBy(i => i).First(i => i.Count() % 2 == 1).Key;
    return result;
  }
}