| 1 | 1 | class Zipper: |
| 2 | | # Tree is a dict with keys "value" (int), "left" (dict or None), "right" (dict or None) |
| 2 | def __init__(self, tree, path): |
| 3 | self.tree = tree |
| 4 | self.path = path |
| 5 | |
| 6 | # Edge Case: Handle empty tree in from_tree |
| 3 | 7 | @staticmethod |
| 4 | 8 | def from_tree(tree: dict) -> "Zipper": |
| 5 | | pass |
| 9 | if not tree: |
| 10 | return None |
| 11 | return Zipper(tree, []) |
| 6 | 12 | |
| 13 | # Edge Case: Handle None zipper in value |
| 7 | 14 | def value(self) -> int: |
| 8 | | pass |
| 15 | if not self.tree: |
| 16 | return None |
| 17 | return self.tree["value"] |
| 9 | 18 | |
| 19 | # Edge Case: Handle None zipper in set_value |
| 10 | 20 | def set_value(self, value: int) -> "Zipper": |
| 11 | | pass |
| 21 | if not self.tree: |
| 22 | return self |
| 23 | new_tree = {"value": value, "left": self.tree["left"], "right": self.tree["right"]} |
| 24 | new_path = [] |
| 25 | for breadcrumb in self.path: |
| 26 | if breadcrumb[0] == "left": |
| 27 | parent = {"value": breadcrumb[1], "left": new_tree, "right": breadcrumb[3]} |
| 28 | else: # breadcrumb[0] == "right" |
| 29 | parent = {"value": breadcrumb[1], "left": breadcrumb[2], "right": new_tree} |
| 30 | new_tree = parent |
| 31 | new_path.append(breadcrumb) |
| 32 | return Zipper(new_tree, []) |
| 12 | 33 | |
| 34 | # Edge Case: Handle None zipper or missing left child in left |
| 13 | 35 | def left(self) -> "Zipper | None": |
| 14 | | pass |
| 36 | if not self.tree or not self.tree["left"]: |
| 37 | return None |
| 38 | new_path = self.path + [("left", self.tree["value"], None, self.tree["right"])] |
| 39 | return Zipper(self.tree["left"], new_path) |
| 15 | 40 | |
| 41 | # Edge Case: Handle None zipper in set_left |
| 16 | 42 | def set_left(self, tree: dict | None) -> "Zipper": |
| 17 | | pass |
| 43 | if not self.tree: |
| 44 | return self |
| 45 | new_tree = {"value": self.tree["value"], "left": tree, "right": self.tree["right"]} |
| 46 | new_path = [] |
| 47 | for breadcrumb in self.path: |
| 48 | if breadcrumb[0] == "left": |
| 49 | parent = {"value": breadcrumb[1], "left": new_tree, "right": breadcrumb[3]} |
| 50 | else: # breadcrumb[0] == "right" |
| 51 | parent = {"value": breadcrumb[1], "left": breadcrumb[2], "right": new_tree} |
| 52 | new_tree = parent |
| 53 | new_path.append(breadcrumb) |
| 54 | return Zipper(new_tree, []) |
| 18 | 55 | |
| 56 | # Edge Case: Handle None zipper or missing right child in right |
| 19 | 57 | def right(self) -> "Zipper | None": |
| 20 | | pass |
| 58 | if not self.tree or not self.tree["right"]: |
| 59 | return None |
| 60 | new_path = self.path + [("right", self.tree["value"], self.tree["left"], None)] |
| 61 | return Zipper(self.tree["right"], new_path) |
| 21 | 62 | |
| 63 | # Edge Case: Handle None zipper in set_right |
| 22 | 64 | def set_right(self, tree: dict | None) -> "Zipper": |
| 23 | | pass |
| 65 | if not self.tree: |
| 66 | return self |
| 67 | new_tree = {"value": self.tree["value"], "left": self.tree["left"], "right": tree} |
| 68 | new_path = [] |
| 69 | for breadcrumb in self.path: |
| 70 | if breadcrumb[0] == "left": |
| 71 | parent = {"value": breadcrumb[1], "left": new_tree, "right": breadcrumb[3]} |
| 72 | else: # breadcrumb[0] == "right" |
| 73 | parent = {"value": breadcrumb[1], "left": breadcrumb[2], "right": new_tree} |
| 74 | new_tree = parent |
| 75 | new_path.append(breadcrumb) |
| 76 | return Zipper(new_tree, []) |
| 24 | 77 | |
| 78 | # Edge Case: Handle None zipper or root node (no path) in up |
| 25 | 79 | def up(self) -> "Zipper | None": |
| 26 | | pass |
| 80 | if not self.path: |
| 81 | return None |
| 82 | breadcrumb = self.path[-1] |
| 83 | direction, parent_value, left_tree, right_tree = breadcrumb |
| 84 | parent_tree = {"value": parent_value, "left": left_tree, "right": right_tree} |
| 85 | if direction == "left": |
| 86 | parent_tree["left"] = self.tree |
| 87 | else: # direction == "right" |
| 88 | parent_tree["right"] = self.tree |
| 89 | return Zipper(parent_tree, self.path[:-1]) |
| 27 | 90 | |
| 91 | # Edge Case: Handle None zipper in to_tree |
| 28 | 92 | def to_tree(self) -> dict: |
| 29 | | pass |
| 93 | if not self.tree: |
| 94 | return None |
| 95 | result = self.tree |
| 96 | for breadcrumb in reversed(self.path): |
| 97 | direction, parent_value, left_tree, right_tree = breadcrumb |
| 98 | parent_tree = {"value": parent_value, "left": left_tree, "right": right_tree} |
| 99 | if direction == "left": |
| 100 | parent_tree["left"] = result |
| 101 | else: # direction == "right" |
| 102 | parent_tree["right"] = result |
| 103 | result = parent_tree |
| 104 | return result |
| 105 | # Handled Edge Cases: Empty tree in from_tree, None zipper in value, None zipper in set_value, None zipper or missing left child in left, None zipper in set_left, None zipper or missing right child in right, None zipper in set_right, None zipper or root node (no path) in up, None zipper in to_tree |