heap operations - 1.cs

using System;
					
public class Program
{
	public class Heap
	{
		int[] heap;
		int elements;
		
		//will have children nodes arr[2*i + 1] and arr[2*i + 2], 
		//and parent node arr[(i-1)/2].
			
		public void Swap(ref int a, ref int b)
		{
			int temp = b;
			b = a;
			a = temp;
		}
		
		public void Insert(int val)
		{
			heap[elements] = val;
			
			int i=elements;
			while (heap[(i-1)/2] < heap[i])
			{
				Swap(ref heap[(i-1)/2], ref heap[i]);
				i = (i-1) /2;
			}
						
			elements++;
		}
		
		public void DeleteRoot()
		{
			int i = 0;
			Swap(ref heap[i], ref heap[elements-1]);
			elements--;
			
			while (2*i + 2 < elements)
			{
				int leftChild = 2*i + 1;
				int rightChild = 2*i + 2;
				
				if (heap[leftChild] > heap[rightChild])
				{
					Swap(ref heap[i], ref heap[leftChild]);	
					i = leftChild;
				} 
				else
				{
					Swap(ref heap[i], ref heap[rightChild]);
					i = rightChild;
				}
			}
		}
		
		public void Display()
		{
			int levels = (int)Math.Log(elements, 2);
			int currentLevel = 0;
			
			int j=1;
			for (int i=0;i<elements;i++)
			{
				if (i == j)
				{
					j=j*2+1;
					Console.WriteLine();
					currentLevel++;
				}			

				Console.Write("{0, -5}", heap[i]);
			}
		}
		
		public Heap(int size)
		{
			heap = new int[size];
			elements = 0;
		}
	}
	
	public static void Main()
	{
		var x = new Random();
		int size = x.Next(10)+1;
		var h = new Heap(size);

		for (int i=0;i<size;i++)
		{
			h.Insert(x.Next(50)+1);
		} 
		
		h.Display();
		
		Console.WriteLine();
		Console.WriteLine();
		
		h.DeleteRoot();
		h.Display();
	}
}