226. Invert Binary Tree | LeetCode | DSA | Problem Solving

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

void swap(TreeNode* &left, TreeNode* &right){
    TreeNode* temp = left;
    left = right;
    right = temp;
}

class Solution {
public:
    TreeNode* invertTree(TreeNode* root) {
        if(root != nullptr){
            invertTree(root->left);
            invertTree(root->right);
            swap(root->left, root->right);
        }
        return root;
    }
};