Mirror a Binary Tree

Bronze

10000ms500MB

Given the root of a binary tree, mirror it by swapping the left and right children of every node. Return the root of the mirrored tree.

Tree Encoding

Your function receives root as a TreeNode (or the empty tree, as null) and returns the root of the mirrored tree. The node type is provided for you, with val, left and right fields; you may mirror in place and return the same root.

The examples below write trees as their level-order traversal, where null marks a missing child of a listed node and trailing nulls are omitted. That is only how trees are displayed; the encoding and decoding are done for you.

Constraints

The number of nodes in the tree is in the range $[0, 100]$ .
$-100 \leq$ Node.val $\leq 100$

Examples

Example 1

Input

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

root

Output

[4, 7, 2, 9, 6, 3, 1]

Explanation

The children of every node are swapped: 2 and 7 trade places under the root, 1 and 3 trade places under 2, and 6 and 9 under 7.

Example 2

Input

root = [2, 1, 3]

root

Output

[2, 3, 1]

Example 3

Input

root = []

Output

[]

Explanation

The empty tree mirrors to itself.

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Mirror a Binary Tree

Bronze

10000ms500MB

Asked atSiemens

Given the root of a binary tree, mirror it by swapping the left and right children of every node. Return the root of the mirrored tree.

Tree Encoding

Constraints

The number of nodes in the tree is in the range $[0, 100]$ .
$-100 \leq$ Node.val $\leq 100$

Examples

Example 1

Input

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

root

Output

[4, 7, 2, 9, 6, 3, 1]

Explanation

The children of every node are swapped: 2 and 7 trade places under the root, 1 and 3 trade places under 2, and 6 and 9 under 7.

Example 2

Input

root = [2, 1, 3]

root

Output

[2, 3, 1]

Example 3

Input

root = []

Output

[]

Explanation

The empty tree mirrors to itself.

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Click "Run" to test with sample cases or "Submit" to run all tests.