226. Invert Binary Tree
/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: TreeNode* invertTree(TreeNode* root) { if (root == NULL) return root; TreeNode* left = invertTree(root->left); TreeNode* right = invertTree(root->right); root->left = right; root->right = left; return root; } };