Leetcode 226 Invert Binary Tree 二叉树

交换左右叶子节点

 /**
  * 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:
     void swapLR(TreeNode* root){
         if(!root) return;
         else{
             TreeNode *t = root->left;
             root->left = root->right;
             root->right = t;
             swapLR(root->left);
             swapLR(root->right);
         }

     }
     TreeNode* invertTree(TreeNode* root) {
         swapLR(root);
         return root;
     }
 };