Method rightSideView

python/0199-binary-tree-right-side-view.py:8–24

(self, root: TreeNode)

#         self.right = right
class Solution:
    def rightSideView(self, root: TreeNode) -> List[int]:
        res = []
        q = collections.deque([root])

        while q:
            rightSide = None
            qLen = len(q)

            for i in range(qLen):
                node = q.popleft()
                if node:
                    rightSide = node
                    q.append(node.left)
                    q.append(node.right)
            if rightSide:
                res.append(rightSide.val)
        return res