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

namespace ConsoleApplication1
{
    class Heap
    {

        public int[] Input;
        public int n;

        public Heap(int[] Input)
        {
            n = Input.Length;
            int[] temp = new int[n+1];
            for (int i = 0; i < Input.Length; ++i)
            {
                temp[i] = Input[i];
            }
            this.Input = temp;
        }

        public void HeapCorrectOrder()
        {
            int[] temp = new int[n];
            for (int i = 0; i < n; i++)
            {
                temp[i] = Input[n - i-1];
            }
            Input = temp;

        }

        public void HeapConstruct()
        {
            int i;
            int temp;
            for (i = n / 2 - 1; i >= 0; i--)
            {
                DownShift(i, n);
            }
            for (i = n - 1; i >= 1; i--)
            {
                temp = Input[0];
                Input[0] = Input[i];
                Input[i] = temp;
                DownShift(0, i - 1);
            }
            HeapCorrectOrder();
        }
        public void DownShift(int Value, int start)
        {
            bool completion = false;
            int ChildBig;
            int temp;

            while ((Value * 2 <= start) && (completion != true))
            {
                if ((Value * 2 == start))
                {
                    ChildBig = Value * 2;
                }
                else if (Input[Value * 2] > Input[Value * 2 + 1])
                {
                    ChildBig = Value * 2;
                }
                else
                {
                    ChildBig = Value * 2 + 1;
                }
                if (Input[Value] < Input[ChildBig])
                {
                    temp = Input[Value];
                    Input[Value] = Input[ChildBig];
                    Input[ChildBig] = temp;
                    Value = ChildBig;
                }
                else
                {
                    completion = true;
                }
            }
        }



    }
}



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

namespace ConsoleApplication1
{
    class Program
    {

        static void Main(string[] args)
        {
            int[] Input = new int[10] {13, 34, 19, 24, 2, 1, 26, 87, 20, 2391};
            Heap Heap = new Heap(Input);
            Heap.HeapConstruct();
            for (int i = 0; i < Heap.n; ++i)
            {
                Console.Write(Heap.Input[i]);
                if (i < Heap.n-1)
                    Console.Write(", ");
            }
        }

    }
}