Description
Invert a binary tree.
Example
Input: [4,2,7,1,3,6,9], Output: [4, 7, 2, 9, 6, 3, 1]
Idea
Recursively invert the left and right tree, rewire them to the root.
Solution
class Solution {
public:
TreeNode* invertTree(TreeNode* root) {
if (!root) return NULL;
TreeNode *left = invertTree(root->left), *right = invertTree(root->right);
root->left = right;
root->right = left;
return root;
}
};
68 / 68 test cases passed.
Runtime: 0 ms
