使用python获取二叉树中给定级别上的所有节点

class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def get_nodes_at_level(root, level):
    if root is None:
        return []

    if level == 1:
        return [root.val]

    left_nodes = get_nodes_at_level(root.left, level - 1)
    right_nodes = get_nodes_at_level(root.right, level - 1)

    return left_nodes + right_nodes

# 示例二叉树
#        1
#       / \
#      2   3
#     / \   \
#    4   5   6
#           /
#          7
# 获取第3级别上的所有节点
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.left = TreeNode(4)
root.left.right = TreeNode(5)
root.right.right = TreeNode(6)
root.right.right.left = TreeNode(7)

level = 3
nodes = get_nodes_at_level(root, level)
print(f"第{level}级别上的所有节点：{nodes}")

第3级别上的所有节点：[4, 5, 6]