226. Invert Binary Tree My Submissions Question

 把题目看成按大小排列翻转，我也是醉了哈哈哈。然后写了一个这样的，当然不过啦，后来认真看题目，发现还只是一道很简单的树翻转题目而已，自己想太多。

/**
 * 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) return 0;
        else
        {
            TreeNode* temp = root -> left;
            root -> left = root -> right;
            root -> right = temp;
            invertTree(root -> left);
            invertTree(root -> right);
            return root;
        }
    }
};