Contributing code for Heap data structure, and

all basic operations associated with it.

Author: Ankit Agarwal

data_structures/Heap/heap.py

@@ -0,0 +1,84 @@
+#!/usr/bin/python
+
+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):
+		for item in self.h:
+			print item,
+
+def main():
+	l = list(map(int,raw_input().split()))
+	h = Heap()
+	h.buildHeap(l)
+	h.heapSort()
+	h.display()
+
+if __name__=='__main__':
+	main()
+
+