Code
Randomized_Select(A,p,r,i)
{
    if p==r
        then return A[p]
    q=Randomized_Partition(A,p,r)
    k=q-p+1
    if i==k
        then return A[q]
    else if i<k
        then return Randomized_select(A,p,q-1,i)
    else
        return Randomized_select(A,q+1,r,i-k)
}

=====================================
Randomized_Partition(A,p,r)
{
    i=RANDOW(p,r)
    exchange A[r] ↔ A[i]
    return Partition(A,p,r)
}
=====================================
Partition(A,p,r)
{
    x=A[r]
    i=p-1
    for j=p to r-1
        if A[j]<=x
              then i=i+1
                  exchange A[i]↔A[j]
    exchange A[i+1] ↔A[r]
    return i+1
}

Codenamespace SelectMinimum{class Program    {static void Main(string[] args)        {int[] A = new int[] {0,25,12,14,57,45,18,75,85,74,45,63,35,28,39 };            SelectSort ss = new SelectSort();int result;            result=ss.Randomized_Select(A,0,14,11);            Console.WriteLine(result);            Console.ReadLine();        }

    }

public class SelectSort    {public int Randomized_Select(int[] A, int p, int r, int i)        {if (p == r)return A[p];int q = Randomize_Partition(A, p, r);int k = q - p + 1;if (i == k)return A[q];else if (i < k)return Randomized_Select(A, p, q - 1, i);elsereturn Randomized_Select(A, q + 1, r, i - k);

        }

public int Randomize_Partition(int[] A, int p, int r)        {            Random rd = new Random();int i = rd.Next(p, r);int temp;            temp = A[r];            A[r] = A[i];            A[i] = temp;return Partition(A, p, r);        }

public int Partition(int[] A, int p, int r)        {int x = A[r];int i = p - 1;for (int j = p; j <= r - 1; j++)            {if (A[j] <= x)                {                    i += 1;int temp;                    temp = A[i];                    A[i] = A[j];                    A[j] = temp;                }            }int temp2;            temp2 = A[i + 1];            A[i + 1] = A[r];            A[r] = temp2;return i + 1;        }    }}