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https://github.com/autistic-symposium/master-algorithms-py.git
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65 lines
1.3 KiB
Python
Executable File
65 lines
1.3 KiB
Python
Executable File
#!/usr/bin/env python
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__author__ = "bt3"
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from binary_search_tree import BST, Node
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from binary_tree import BT, Node
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def isBST(node, min_node=float("-infinity"), maxVal=float("infinity")):
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if not node:
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return True
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if not min_node <= node.item <= maxVal:
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return False
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return isBST(node.left, min_node, node.item) and \
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isBST(node.right, node.item, maxVal)
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def isBST_other_method(node, max_node=None, min_node=None):
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if not node:
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return True
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left, right = True, True
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min_node = min_node or float('inf')
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max_node = max_node or -float('inf')
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if node.left:
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if node.left.item > node.item or node.left.item > max_node:
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left = False
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else:
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max_node = node.item
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left = isBST(node.left, max_node, min_node)
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if node.right:
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if node.right.item < node.item or node.right.item < min_node:
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rihjt = False
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else:
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min_node = node.item
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right = isBST(node.right, max_node, min_node)
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return left and right
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if __name__ == '__main__':
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bt = BST()
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for i in range(1, 10):
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bt.add(i)
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assert(isBST(bt.root) == True)
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bt = BT()
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for i in range(1, 10):
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bt.add(i)
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assert(isBST(bt.root) == False)
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