题解 | #翻转牛群结构#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return TreeNode类
     */

    TreeNode* invertTree(TreeNode* root) {
        // write code here

        if(!root)
            return root;

        if(root->left || root->right)
        {
            TreeNode* t = root->left;
            root->left = root->right;
            root->right = t;
        }

        invertTree(root->left);
        invertTree(root->right);

        return root;
    }
};