226.Invert Binary Tree

tags: Easy,Tree,BFS,DFS,Binary Tree

226. Invert Binary Tree

題目描述

Given the root of a binary tree, invert the tree, and return its root.

範例

Example 1:

Input: root = [4,2,7,1,3,6,9]
Output: [4,7,2,9,6,3,1]

Example 2:

Input: root = [2,1,3]
Output: [2,3,1]

Example 3:

Input: root = []
Output: []

Constraints:

• The number of nodes in the tree is in the range [0, 100].
• -100 <= Node.val <= 100

解答

Python

class Solution:
    def invertTree(self, root: Optional[TreeNode]) -> Optional[TreeNode]:
        if not root: return
        root.left, root.right = self.invertTree(root.right), self.invertTree(root.left)
        return root

Ron ChenSat, Feb 18, 2023

Javascript

function invertTree(root) {
  if (root === null) return null;

  const queue = [root];
  while (queue.length) {
    const node = queue.shift();
    const temp = node.left;
    node.left = node.right;
    node.right = temp;
    if (node.left) queue.push(node.left);
    if (node.right) queue.push(node.right);
  }

  return root;
}

MarsgoatFeb 20, 2023

Reference

https://twitter.com/mxcl/status/608682016205344768

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