Python实现小根堆操作

# from pythonds.trees.binheap import BinHeap

class BinHeap:
	def __init__(self):
		self.heapList = [0]
		self.currentSize = 0

	def percUp(self, i):
		while i // 2 > 0 :
			if self.heapList[i] < self.heapList[i//2]:
				tmp = self.heapList[i//2]
				self.heapList[i//2] = self.heapList[i]
				self.heapList[i] = tmp
			i //= 2

	def insert(self, k):
		self.heapList.append(k)
		self.currentSize = self.currentSize + 1
		self.percUp(self.currentSize)

	def percDown(self, i):
		while (i*2) <= self.currentSize:
			mc = self.minChild(i)
			if self.heapList[i] > self.heapList[mc]:
				tmp = self.heapList[i]
				self.heapList[i] = self.heapList[mc]
				self.heapList[mc] = tmp
			i = mc

	def minChild(self, i):
		if i*2+1 > self.currentSize:
			return i*2
		else:
			if self.heapList[i*2] < self.heapList[i*2+1]:
				return i*2
			else:
				return i*2+1

	def delMin(self):
		retval = self.heapList[1]
		self.heapList[1] = self.heapList[self.currentSize]
		self.currentSize = self.currentSize - 1
		self.heapList.pop()
		self.percDown(1)
		return retval

	def buildHeap(self, alist):
		i = len(alist) // 2
		self.currentSize = len(alist)
		self.heapList = [0] + alist[:]
		while (i>0):
			self.percDown(i)
			i -= 1

if __name__ == '__main__':
	'''
	bh = BinHeap()
	bh.insert(5)
	bh.insert(7)
	bh.insert(3)
	bh.insert(11)
	
	print(bh.delMin())
	print(bh.delMin())
	print(bh.delMin())
	print(bh.delMin())
	'''

	bh = BinHeap()
	bh.buildHeap([9, 5, 6, 2, 3])

	print(bh.delMin())
	print(bh.delMin())
	print(bh.delMin())
	print(bh.delMin())
	print(bh.delMin())