Binary Search Tree Iterator
# Definition for a binary tree node
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class BSTIterator(object):
def __init__(self, root):
"""
:type root: TreeNode
"""
self.stack = []
while root:
self.stack.append(root)
root = root.left
def hasNext(self):
"""
:rtype: bool
"""
return len(self.stack) > 0
def next(self):
"""
:rtype: int
"""
node = self.stack.pop()
x = node.right
while x:
self.stack.append(x)
x = x.left
return node.val
# Your BSTIterator will be called like this:
# i, v = BSTIterator(root), []
# while i.hasNext(): v.append(i.next())
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