题解 | #牛牛的二叉树后序遍历#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
 
class Solution {
public:
    vector<int> ans;

    //递归法
    void LRD(TreeNode* cur){
        if(!cur) return;
        LRD(cur->left);
        LRD(cur->right);
        ans.push_back(cur->val);
    }
    vector<int> postorderTraversal(TreeNode* root) {
        LRD(root);
        return ans;
    }
};