struct TreeNode {

    int val;

    TreeNode* left;

    TreeNode* right;

    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}

};

vector<int> rightSideView(TreeNode* root) {

    unordered_map<int, int> rightmostValueAtDepth;

    int max_depth = -1;

    queue<TreeNode*> nodeQueue;

    queue<int> depthQueue;

    nodeQueue.push(root);

    depthQueue.push(0);

    while (!nodeQueue.empty()) {

       TreeNode* node = nodeQueue.front(); nodeQueue.pop();

       int depth = depthQueue.front(); depthQueue.pop();

       if (node != NULL) {

           max_depth = max(max_depth, depth);

           rightmostValueAtDepth[depth] = node->val;

           nodeQueue.push(node->left);

           nodeQueue.push(node->right);

           depthQueue.push(________);

           depthQueue.push(________);

       }

    }

    vector<int> rightView;

    for (int depth = 0; ________; ++depth) {

        rightView.push_back(rightmostValueAtDepth[depth]);

    }

    return rightView;

};