iddfs.py

def iddfs():
    root = get_root()
    res = float("inf")

    def iddfs_search(node, depth, limit):
        if depth <= limit and node is not None:
            val = node.val
            if val >= 10:
                nonlocal res
                res = min(res, depth)
            else:
                iddfs_search(node.left, depth + 1, limit)
                iddfs_search(node.right, depth + 1, limit)

    for limit in range(1, 5):
        print("max depth: ", limit)
        iddfs_search(root, 0, limit)
        if res < float("inf"):
            return res
    return -1