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226-invertBinaryTree.js
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226-invertBinaryTree.js
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//URL--
// https://leetcode.com/problems/invert-binary-tree/
//INSTRUCTIONS--
/* Given the root of a binary tree, invert the tree, and return its root.
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
*/
//SOLUTION--
/*
Until the node is null
Switch the right and left node on the current node
Swap the right and left node of each child node
return the root node
*/
/**
* Definition for a binary tree node.
* function TreeNode(val, left, right) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
*/
/**
* @param {TreeNode} root
* @return {TreeNode}
*/
const invertTree = function (root) {
//if the root is null, return null
if (root === null) {
return null
}
const right = root.right
const left = root.left
//swap the left and right branches
root.left = right
root.right = left
//invert the left and right branches of the tree
invertTree(root.left)
invertTree(root.right)
//return the root
return root
};
function TreeNode(val, left, right) {
this.val = (val === undefined ? 0 : val)
this.left = (left === undefined ? null : left)
this.right = (right === undefined ? null : right)
}