| 1 | 1 | class Zipper: |
| 2 | def __init__(self, tree, path=None): |
| 3 | # Edge Case: Handle None tree by initializing with empty dict |
| 4 | self.tree = tree if tree is not None else {"value": 0, "left": None, "right": None} |
| 5 | # Path is a list of tuples (parent_tree, is_left_child) |
| 6 | self.path = path if path is not None else [] |
| 7 | |
| 2 | 8 | # Tree is a dict with keys "value" (int), "left" (dict or None), "right" (dict or None) |
| 3 | 9 | @staticmethod |
| 4 | 10 | def from_tree(tree: dict) -> "Zipper": |
| 5 | | pass |
| 11 | # Edge Case: Handle None input tree |
| 12 | if tree is None: |
| 13 | return Zipper(None) |
| 14 | return Zipper(tree) |
| 6 | 15 | |
| 7 | 16 | def value(self) -> int: |
| 8 | | pass |
| 17 | return self.tree["value"] |
| 9 | 18 | |
| 10 | 19 | def set_value(self, value: int) -> "Zipper": |
| 11 | | pass |
| 20 | # Edge Case: Create new tree to maintain immutability |
| 21 | new_tree = {"value": value, "left": self.tree["left"], "right": self.tree["right"]} |
| 22 | if not self.path: |
| 23 | return Zipper(new_tree, self.path) |
| 24 | return Zipper(new_tree, self.path) |
| 12 | 25 | |
| 13 | 26 | def left(self) -> "Zipper | None": |
| 14 | | pass |
| 27 | # Edge Case: Handle None left child |
| 28 | if self.tree["left"] is None: |
| 29 | return None |
| 30 | # Edge Case: Track path for navigation back up |
| 31 | new_path = self.path + [(self.tree, True)] |
| 32 | return Zipper(self.tree["left"], new_path) |
| 15 | 33 | |
| 16 | 34 | def set_left(self, tree: dict | None) -> "Zipper": |
| 17 | | pass |
| 35 | # Edge Case: Create new tree to maintain immutability |
| 36 | new_tree = {"value": self.tree["value"], "left": tree, "right": self.tree["right"]} |
| 37 | if not self.path: |
| 38 | return Zipper(new_tree, self.path) |
| 39 | return Zipper(new_tree, self.path) |
| 18 | 40 | |
| 19 | 41 | def right(self) -> "Zipper | None": |
| 20 | | pass |
| 42 | # Edge Case: Handle None right child |
| 43 | if self.tree["right"] is None: |
| 44 | return None |
| 45 | # Edge Case: Track path for navigation back up |
| 46 | new_path = self.path + [(self.tree, False)] |
| 47 | return Zipper(self.tree["right"], new_path) |
| 21 | 48 | |
| 22 | 49 | def set_right(self, tree: dict | None) -> "Zipper": |
| 23 | | pass |
| 50 | # Edge Case: Create new tree to maintain immutability |
| 51 | new_tree = {"value": self.tree["value"], "left": self.tree["left"], "right": tree} |
| 52 | if not self.path: |
| 53 | return Zipper(new_tree, self.path) |
| 54 | return Zipper(new_tree, self.path) |
| 24 | 55 | |
| 25 | 56 | def up(self) -> "Zipper | None": |
| 26 | | pass |
| 57 | # Edge Case: Handle navigation beyond root (no parent) |
| 58 | if not self.path: |
| 59 | return None |
| 60 | parent_tree, is_left_child = self.path[-1] |
| 61 | new_path = self.path[:-1] |
| 62 | |
| 63 | # Reconstruct parent with current tree as child |
| 64 | reconstructed = { |
| 65 | "value": parent_tree["value"], |
| 66 | "left": self.tree if is_left_child else parent_tree["left"], |
| 67 | "right": parent_tree["right"] if is_left_child else self.tree |
| 68 | } |
| 69 | |
| 70 | return Zipper(reconstructed, new_path) |
| 27 | 71 | |
| 28 | 72 | def to_tree(self) -> dict: |
| 29 | | pass |
| 73 | # Navigate back to root to get complete tree |
| 74 | current = self |
| 75 | while current.path: |
| 76 | current = current.up() |
| 77 | return current.tree |
| 78 | |
| 79 | # Handled Edge Cases: None tree input, None left/right child, navigation beyond root, immutability preservation |