11.Binary Tree Right Side View

Example:

Input: [1,2,3,null,5,null,4]
Output: [1, 3, 4]

Explanation:

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

Solution : (Level Order traversal last node)

class Solution
{
public:
    vector<int> rightSideView(TreeNode *root)
    {
        vector<int> v;
        
        if(root == NULL)
        {
            return v;
        }

        TreeNode *t = NULL;
        queue<TreeNode *> q;
        q.push(root);

        while (!q.empty())
        {

            int s = q.size();
            while (s > 0)
            {
                t = q.front();
                q.pop();

                if (t->left)
                {
                    q.push(t->left);
                }

                if (t->right)
                {
                    q.push(t->right);
                }

                if (s == 1)
                {
                    v.push_back(t->val);
                }
                s--;
            }
        }
        return v;
    }
};