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55 lines
1.1 KiB
Python
55 lines
1.1 KiB
Python
"""
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226. Invert Binary Tree
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Difficulty: Easy
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https://leetcode.com/problems/invert-binary-tree/
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──────────────────────────────────────────────────
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Given the root of a binary tree, invert the tree, and return its root.
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Example 1:
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Input: root = [4,2,7,1,3,6,9]
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Output: [4,7,2,9,6,3,1]
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Example 2:
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Input: root = [2,1,3]
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Output: [2,3,1]
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Example 3:
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Input: root = []
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Output: []
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Constraints:
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• The number of nodes in the tree is in the range [0, 100].
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• -100 <= Node.val <= 100
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"""
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# Definition for a binary tree node.
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# class TreeNode:
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# def __init__(self, val=0, left=None, right=None):
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# self.val = val
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# self.left = left
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# self.right = right
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class Solution:
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def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
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if not root:
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return None
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left = self.invertTree(root.left)
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right = self.invertTree(root.right)
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root.left = right
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root.right = left
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return root
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