题解 | #二叉树的中序遍历#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
public:
    /**
     * 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 int整型vector
     */
    vector<int> inorderTraversal(TreeNode* root) {
        std::vector<int> vec;
        if (root == nullptr) {
            return vec;
        }

        if (root->left) {
            std::vector<int> left = inorderTraversal(root->left);
            vec.insert(vec.end(), left.begin(), left.end());
        }

        vec.emplace_back(root->val);
        
        if (root->right) {
            std::vector<int> right = inorderTraversal(root->right);
            vec.insert(vec.end(), right.begin(), right.end());
        }
        return vec;
    }
};