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|
from collections import deque
class Node(object):
def __init__(self, value, left=None, right=None):
self.value = value
self.left = left
self.right = right
def is_bst(self):
s = []
s.append((float('-inf'), self, float('inf')))
while s:
lo, node, hi = s.pop()
if lo <= node.value <= hi:
node.left and s.append((lo, node.left, node.value))
node.right and s.append((node.value, node.right, hi))
else:
return False
return True
x = Node(
50,
Node(
17,
Node(
12,
Node(9),
Node(14),
),
Node(
23,
Node(19),
),
),
Node(
72,
Node(
54,
None,
Node(67)
),
Node(76),
),
)
assert x.is_bst()
print("Success!")
|
