Right View of Binary Tree.cpp

/*
Right View of Binary Tree
=========================

Given a Binary Tree, find Right view of it. Right view of a Binary Tree is set of nodes visible when tree is viewed from right side.

Right view of following tree is 1 3 7 8.

          1
       /     \
     2        3
   /   \      /    \
  4     5   6    7
    \
     8

Example 1:
Input:
       1
    /    \
   3      2
Output: 1 2

Example 2:
Input:
     10
    /   \
  20     30
 /   \
40  60 
Output: 10 30 60
Your Task:
Just complete the function rightView() that takes node as parameter and returns the right view as a list. 

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(Height of the Tree).

Constraints:
0 ≤ Number of nodes ≤ 105
1 ≤ Data of a node ≤ 105
*/

vector<int> rightView(Node *root)
{
  if (!root)
    return {};
  vector<int> ans;
  queue<Node *> q;
  q.push(root);

  while (q.size())
  {
    int size = q.size();
    for (int i = size; i > 0; --i)
    {
      auto curr = q.front();
      q.pop();
      if (i == 1)
        ans.push_back(curr->data);

      if (curr->left)
        q.push(curr->left);
      if (curr->right)
        q.push(curr->right);
    }
  }

  return ans;
}