Max Heap

gistfile1.rb

class MaxHeap

  def self.heapify(arr, i)
    l = left(i)
    r = right(i)
    heap_size = arr.size - 1

    if l <= heap_size && arr[l] > arr[i]
      largest = l 
    else
      largest = i 
    end

    if r <= heap_size - 1 && arr[r] > arr[largest]
      largest = r
    end

    unless largest == i
      arr[i], arr[largest] = arr[largest], arr[i]
      heapify(arr, largest) 
    end

    arr
  end

  private

  def self.left(i)
    2 * i + 1
  end

  def self.right(i)
    2 * i + 2
  end

end