Python/data_structures/Heap/heap.py

#!/usr/bin/python

from __future__ import print_function

try:
    raw_input          # Python 2
except NameError:
    raw_input = input  # Python 3

class Heap:
	def __init__(self):
	    self.h = []
	    self.currsize = 0

	def leftChild(self,i):
		if 2*i+1 < self.currsize:
			return 2*i+1
		return None

	def rightChild(self,i):
		if 2*i+2 < self.currsize:
			return 2*i+2
		return None

	def maxHeapify(self,node):
		if node < self.currsize:
			m = node
			lc = self.leftChild(node)
			rc = self.rightChild(node)
			if lc is not None and self.h[lc] > self.h[m]:
				m = lc
			if rc is not None and self.h[rc] > self.h[m]:
				m = rc
			if m!=node:
				temp = self.h[node]
				self.h[node] = self.h[m]
				self.h[m] = temp
				self.maxHeapify(m)

	def buildHeap(self,a):
		self.currsize = len(a)
		self.h = list(a)
		for i in range(self.currsize/2,-1,-1):
			self.maxHeapify(i)

	def getMax(self):
		if self.currsize >= 1:
			me = self.h[0]
			temp = self.h[0]
			self.h[0] = self.h[self.currsize-1]
			self.h[self.currsize-1] = temp
			self.currsize -= 1
			self.maxHeapify(0)
			return me
		return None

	def heapSort(self):
		size = self.currsize
		while self.currsize-1 >= 0:
			temp = self.h[0]
			self.h[0] = self.h[self.currsize-1]
			self.h[self.currsize-1] = temp
			self.currsize -= 1
			self.maxHeapify(0)
		self.currsize = size

	def insert(self,data):
		self.h.append(data)
		curr = self.currsize
		self.currsize+=1
		while self.h[curr] > self.h[curr/2]:
			temp = self.h[curr/2]
			self.h[curr/2] = self.h[curr]
			self.h[curr] = temp
			curr = curr/2

	def display(self):
		print(self.h)

def main():
	l = list(map(int, raw_input().split()))
	h = Heap()
	h.buildHeap(l)
	h.heapSort()
	h.display()

if __name__=='__main__':
	main()