CareerCup

static void ReGroup(List<int> Numbers)
        {
            int groupCount = 0;
            int groups = Numbers.Count / 3;
            for (int i = 0; i != groups; i++)
            {
                int secOne = Numbers[groupCount];
                groupCount++;
                int secTwo = Numbers[groupCount];
                groupCount++;
                int secTree = Numbers[groupCount];
                groupCount++;
                

                int currnet = groupCount - 1;
                Console.WriteLine(currnet);

                Numbers[currnet] = secOne;
                currnet--;
                Numbers[currnet] = secTwo;
                currnet--;
                Numbers[currnet] = secTree;

            }

        }

void reverseArrSect(int iArr[n],int iSec)
{
	int iTemp = -1;
	cout << endl << "reverse sections of array";
	for(int i=0;i<n;i+=iSec)
	{
		iTemp =  iArr[i];
		iArr[i] = iArr[i+2];
		iArr[i+2] = iTemp;
		cout << iArr[i] <<','<< iArr[i+1] << ','<<iArr[i+2] << ',';
	}
}

Very easy program. Written in c#

private static void ReverseArray() {
			// in C#, given a list of numbers [4,8,20,11,12,18,50,10,11] and divided in sections of 3
			// Reverse each section without using another array
			int[] array = { 4,8,20,11,12,18,50,10,11 };
			
			Console.WriteLine("Original array");
			for(int i=0;i<array.Length;i++) {
				Console.Write("{0} ", array[i]);
			}
			
			// Traverse the array stepping by 3
			for (int i=0; i<array.Length; i+=3) {
				// Just I need to swap first and third
				int temp = array[i];
				array[i] = array[i+2];
				array[i+2] = temp;
			}
			
			Console.WriteLine("Reversed");
			for(int i=0;i<array.Length;i++) {
				Console.Write("{0} ", array[i]);
			}
			
		}