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https://github.com/autistic-symposium/master-algorithms-py.git
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58 lines
1.3 KiB
Python
Executable File
58 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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def find_ancestor(path, low_item, high_item):
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while path:
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current_item = path[0]
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if current_item < low_item:
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try:
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path = path[2:]
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except:
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return current_item
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elif current_item > high_item:
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try:
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path = path[1:]
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except:
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return current_item
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elif low_item <= current_item <= high_item:
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return current_item
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def find_ancestor2(tree, n1, n2):
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if not tree:
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return False
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if n1 <= tree.item and n2 >= tree.item or (not tree.left and not tree.right) :
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return tree.item
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if tree.left and (n1 < tree.item and n2 < tree.item):
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return find_ancestor(tree.left, n1, n2) or tree.item
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if tree.right and (n1 > tree.item and n2 > tree.item):
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return find_ancestor(tree.right, n1, n2) or tree.item
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if __name__ == '__main__':
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bst = BST()
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l = [10, 5, 6, 3, 8, 2, 1, 11, 9, 4]
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for i in l:
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bst.add(i)
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nodes = bst.preorder_array()
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print 'Original: ', l
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print 'Preorder: ', nodes
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print 'Method 1: '
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print 'Ancestor for 3, 11:', find_ancestor(nodes, 3, 11)
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print 'Method 2: '
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print 'Ancestor for 3, 11: ', find_ancestor2(bst.root, 3, 11)
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