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https://github.com/autistic-symposium/master-algorithms-py.git
synced 2025-04-30 12:46:11 -04:00
121 lines
2.5 KiB
Python
Executable File
121 lines
2.5 KiB
Python
Executable File
#!/usr/bin/python
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__author__ = "bt3"
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class Node(object):
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def __init__(self, item=None,):
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self.item = item
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self.left = None
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self.right = None
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def __repr__(self):
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return '{}'.format(self.item)
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def _add(self, value):
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new_node = Node(value)
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if not self.item:
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self.item = new_node.value
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else:
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if value > self.item:
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self.right = self.right and self.right._add(value) or new_node
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elif value < self.item:
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self.left = self.left and self.left._add(value) or new_node
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else:
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print("BSTs do not support repeated items.")
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return self # this is necessary!!!
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def _search(self, value):
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if self.item == value:
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return True # or self
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elif self.left and value < self.item:
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return self.left._search(value)
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elif self.right and value > self.item:
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return self.right._search(value)
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else:
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return False
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def _isLeaf(self):
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return not self.right and not self.left
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def _printPreorder(self):
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print self.item
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if self.left:
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self.left._printPreorder()
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if self.right:
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self.right._printPreorder()
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# Another possibility: use an array (a little bit more expensive):
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def _preorder_array(self):
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nodes = []
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if self.item:
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nodes.append(self.item)
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if self.left:
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nodes.extend(self.left._preorder_array())
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if self.right:
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nodes.extend(self.right._preorder_array())
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return nodes
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class BST(object):
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def __init__(self):
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self.root = None
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def add(self, value):
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if not self.root:
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self.root = Node(value)
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else:
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self.root._add(value)
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def printPreorder(self):
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if self.root:
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self.root._printPreorder()
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def search(self, value):
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if self.root:
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return self.root._search(value)
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def preorder_array(self):
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if self.root:
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return self.root._preorder_array()
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else:
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return 'Tree is empty.'
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if __name__ == '__main__':
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bst = BST()
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print "Adding nodes 1 to 10 in the tree..."
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for i in range(1, 11):
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bst.add(i)
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print
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print "Searching for nodes 16 and 6"
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print bst.search(16)
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print bst.search(6)
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print
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print "Printing preorder..."
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bst.printPreorder()
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