Binary Tree Vertical Order Transveral

class Solution:
    def verticalOrder(self, root: Optional[TreeNode]) -> List[List[int]]:
        if not root:
                return []

        from collections import defaultdict, deque
        q = deque()
        q.append((root, 0, 0))
        hashmap = defaultdict(list)
        min_col = float("inf")
        max_col = -float("inf")

        while q:
            node, col, level = q.popleft()
            if node:  # check if the node is not None
                if col < min_col:
                    min_col = col
                if col > max_col:
                    max_col = col
                hashmap[col].append(node.val)
                q.append((node.left, col - 1, level + 1))
                q.append((node.right, col + 1, level + 1))

        return [hashmap[col] for col in range(min_col, max_col + 1)]