count the occurrence of each distinct item in the array - Seeni, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Microsoft (R) Visual C# Compiler version 2.9.0.63208 (958f2354)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //array = [1,4,2,5,4,2,5,1,6,2,5,3,8,9,6]
            //Write a program to count the occurrence of each distinct item in the array?
            //Builin array functions and LINQ are not allowed.
            
            Console.WriteLine("Start here...");
            int[] nums = { 1, 4, 2, 5, 4, 2, 5, 1, 6, 2, 5, 3, 8, 9, 6 };
            Dictionary<int, int> DupCount = new Dictionary<int, int>();
            for (int i = 0; i < nums.Length; i++)
            {
                if (DupCount.ContainsKey(nums[i]))
                { DupCount[nums[i]] += 1; }
                else { DupCount.Add(nums[i], 1); }
            }
            foreach (var d in DupCount)
            {
                if(d.Value!=1)
                Console.WriteLine("Value="+d.Key+" count= "+d.Value);
            }
                    }
    }
}

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Compilation time: 0,69 sec, absolute running time: 0,09 sec, cpu time: 0,11 sec, average memory usage: 15 Mb, average nr of threads: 3, absolute service time: 0,83 sec