using System;
using System.Linq;
 
public class Test
{
        public static void Main()
        {
               int[] testArray = {1,5,6,8,9,4,4,6,3,2};
 
               var adjacentDuplicate = testArray.Skip(1).Where((value,index) => value == testArray[index]).Distinct();
               Console.WriteLine ("Duplicates " +  adjacentDuplicate.Select (x=>x.ToString()).Aggregate ((a,b) => a+ " " + b));
 
               var adjacentIndex = testArray.Skip(1).Select((value,index) => value == testArray[index] ? index: 0).Where (x=> x!= 0);
               Console.WriteLine ("Index of duplicates " +  adjacentIndex.Select (x=>x.ToString()).Aggregate ((a,b) => a+ " " + b));
 
       }
}

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