题解 | #二叉树的镜像#

/**
 * 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 pRoot TreeNode类
     * @return TreeNode类
     */
    //类后序遍历
    TreeNode* Mirror(TreeNode* pRoot) {
        if (pRoot == nullptr) return nullptr;
        TreeNode* left = pRoot->left;
        pRoot->left = Mirror(pRoot->right);
        pRoot->right = Mirror(left);
        return pRoot;
    }
};