右侧视角的二叉树

class Solution {
public:
vector<int> rightSideView(TreeNode* root) {
int dep = -1;
bfs(root, dep + 1);
vector<int> res;
for(int i = 0; i < ret.size(); ++i){
res.push_back(ret[i][ret[i].size() - 1]);
}
return res;
}

void bfs(TreeNode * root, int depth)
{
if(root == NULL) return;
if(depth < ret.size()){
ret[depth].push_back(root->val);
}else{
vector<int>tmp;
ret.push_back(tmp);
ret[depth].push_back(root->val);
}
if(root->left)
bfs(root->left, depth + 1);
if(root->right)
bfs(root->right, depth + 1);
}
private:
vector<vector<int>> ret;
};