leetCode.94.94. 二叉树的中序遍历

leetCode.94.94. 二叉树的中序遍历

没什么好讲思路的，直接上代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    vector<int> res;
    vector<int> inorderTraversal(TreeNode* root) {
        dfs( root );
        return res;
    }

    void dfs( TreeNode * root ) {
        if ( !root ) return ;

        dfs( root->left );
        res.push_back(root->val);
        dfs( root->right );
    }
};