199. Binary Tree Right Side View

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.

For example: Given the following binary tree,

   1            <---
 /   \
2     3         <---
 \     \
  5     4       <---

You should return [1, 3, 4].

S: DFS

    vector<int> rightSideView(TreeNode* root) {
        vector<int> result;
        getNums(root, 0, result);
        return result;
    }

    void getNums(TreeNode* root, int height, vector<int> &result) {
        if (!root) {
            return;
        }
        if (height == result.size()) {
            result.push_back(root->val);
        }
        getNums(root->right, height+1, result);
        getNums(root->left, height+1, result);
    }