80 lines
1.6 KiB
Python
80 lines
1.6 KiB
Python
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from collections import deque
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class Node(object):
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def __init__(self, value, left=None, right=None):
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self.value = value
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self.left = left
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self.right = right
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def insert_left(self, value):
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self.left = Node(value)
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return self.left
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def insert_right(self, value):
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self.right = Node(value)
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return self.right
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def min(self):
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xs = deque()
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result = float('inf')
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xs.append(self)
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while xs:
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node = xs.popleft()
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result = min(result, node.value)
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if node.left:
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xs.append(node.left)
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if node.right:
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xs.append(node.right)
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return result
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def max(self):
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xs = deque()
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result = float('-inf')
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xs.append(self)
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while xs:
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node = xs.popleft()
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result = max(result, node.value)
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if node.left:
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xs.append(node.left)
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if node.right:
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xs.append(node.right)
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return result
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def is_bst(self):
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result = True
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if self.left:
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result = result and self.left.max() < self.value
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if self.right:
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result = result and self.right.min() > self.value
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return result
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x = Node(
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50,
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Node(
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17,
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Node(
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12,
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Node(9),
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Node(14),
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),
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Node(
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23,
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Node(19),
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),
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),
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Node(
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72,
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Node(
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54,
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None,
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Node(67)
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),
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Node(76),
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),
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)
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assert x.is_bst()
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print("Success!")
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