binary search trees #34
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,59 +1,147 @@ | ||
| class TreeNode: | ||
| def __init__(self, key, val=None): | ||
| if val == None: | ||
| val = key | ||
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| self.key = key | ||
| self.value = val | ||
| self.left = None | ||
| self.right = None | ||
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| def height(self): | ||
| if self.right and self.left: | ||
| return 1 + max(self.left.height(), self.right.height()) | ||
| elif self.left: | ||
| return 1 + self.left.height() | ||
| elif self.right: | ||
| return 1 + self.right.height() | ||
| else: | ||
| return 1 | ||
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| class Tree: | ||
| def __init__(self): | ||
| self.root = None | ||
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| # Time Complexity: O(log N) | ||
| # Space Complexity: O(1) | ||
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| def add_helper(self, current_node, key, value): | ||
|
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There was a problem hiding this comment. The space complexity is O(log n) if the tree is balanced due to the recursive call stack. |
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| if current_node == None: | ||
| return TreeNode(key, value) | ||
| if key <= current_node.key: | ||
| current_node.left = self.add_helper(current_node.left, key, value) | ||
| else: | ||
| current_node.right = self.add_helper( | ||
| current_node.right, key, value) | ||
| return current_node | ||
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| def add(self, key, value=None): | ||
| if self.root == None: | ||
| self.root = TreeNode(key, value) | ||
| else: | ||
| self.add_helper(self.root, key, value) | ||
| # parent = None | ||
| # current = self.root | ||
| # while current != None: | ||
| # parent = current | ||
| # if current.key >= key: | ||
| # current = current.left | ||
| # else: | ||
| # current = current.right | ||
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| # if parent.key > key: | ||
| # parent.left = TreeNode(key, value) | ||
| # else: | ||
| # parent.right = TreeNode(key, value) | ||
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| # Time Complexity: O(n) | ||
| # Space Complexity: O(1) | ||
| def find(self, key): | ||
|
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| if self.root == None: | ||
| return None | ||
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| current = self.root | ||
| while current != None: | ||
| if current.key == key: | ||
| return current.value | ||
| elif current.key < key: | ||
| current = current.right | ||
| else: | ||
| current = current.left | ||
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| return None | ||
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| # Time Complexity: O(n) | ||
| # Space Complexity: O(n) | ||
| def inorder_helper(self, current, traversal_list): | ||
|
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| if not current: | ||
| return traversal_list | ||
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| obj = {'key': current.key, 'value': current.value} | ||
| self.inorder_helper(current.left, traversal_list) | ||
| traversal_list.append(obj) | ||
| self.inorder_helper(current.right, traversal_list) | ||
| return traversal_list | ||
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| def inorder(self): | ||
| traversal_list = [] | ||
| return self.inorder_helper(self.root, traversal_list) | ||
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| # Time Complexity: O(n) | ||
| # Space Complexity:O(n) | ||
| def preorder_helper(self, current, traversal_list): | ||
|
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| if not current: | ||
| return traversal_list | ||
| if current: | ||
| obj = {'key': current.key, 'value': current.value} | ||
| traversal_list.append(obj) | ||
| self.preorder_helper(current.left, traversal_list) | ||
| self.preorder_helper(current.right, traversal_list) | ||
| return traversal_list | ||
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| def preorder(self): | ||
| traversal_list = [] | ||
| return self.preorder_helper(self.root, traversal_list) | ||
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| def postorder_helper(self, current, traversal_list): | ||
| if not current: | ||
| return traversal_list | ||
| if current: | ||
| self.postorder_helper(current.left, traversal_list) | ||
| self.postorder_helper(current.right, traversal_list) | ||
| obj = {'key': current.key, 'value': current.value} | ||
| traversal_list.append(obj) | ||
| return traversal_list | ||
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| # Time Complexity: O(n) | ||
| # Space Complexity: O(n) | ||
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| def postorder(self): | ||
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| traversal_list = [] | ||
| return self.postorder_helper(self.root, traversal_list) | ||
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| # Time Complexity: O(n) | ||
| # Space Complexity: O(n) | ||
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| def height(self): | ||
| if self.root: | ||
| return self.root.height() | ||
| else: | ||
| return 0 | ||
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| # # Optional Method | ||
| # # Time Complexity: | ||
| # # Space Complexity: | ||
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| def bfs(self): | ||
| pass | ||
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| # # Useful for printing | ||
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| def to_s(self): | ||
| return f"{self.inorder()}" | ||
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Interesting putting this on the
TreeNodeclass.