python版线段树

#coding=gbk
#线段树
class Tree(object):
	def __init__(self,l,r):
		self.l = l
		self.r = r
		self.value = 0
		self.left = None
		self.right = None
		if l < r:
			mid = (l + r)/2
			self.left = Tree(l,mid)
			self.right = Tree(mid+1,r)

	def set_value(self,p,value):
		if self.l == self.r:
			self.value = value
			return
		mid = (self.l + self.r)/2
		if p <= mid:
			self.left.set_value(p,value)
		else:
			self.right.set_value(p,value)
		self.push_up()

	def push_up(self):
		self.value = self.left.value + self.right.value

	def query(self,x,y):
		print "query",x,y,'\t',(self.l + self.r)/2,'\t',self.l,self.r,self.value
		if x <= self.l and y>=self.r:
			return self.value
		if self.l == self.r:
			return self.value

		mid = (self.l + self.r)/2
		if mid >= y:
			return self.left.query(x,y)
		elif mid < x:
			return self.right.query(x,y)
		else:
			return self.left.query(x,mid) + self.right.query(mid+1,y)



def main():
	N = 1024
	import time
	old =time.time()
	tree = Tree(0,N)
	for i in xrange(N+1):
		# print i
		tree.set_value(i,1)
	print tree.query(30,60)
	print time.time() -old

if __name__ == "__main__":
	main()