What is the algorithm for checking for new posts in a group in VK?

Question

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There is a task - to repost all new posts from my VK group to the site.
I can't figure out how to correctly check if a new post has appeared, so as not to repost one post to myself twice, or vice versa, not to miss a post.
I thought to get posts using wall.get , check the id of the last post in the group, if it differs from the last one on the site - publish.
But I do not know how to get around the above difficulties.

Answer 1

We make a request to the VK API
We get posts from the wall
We select only those whose ID is greater than the last published one We
publish on the site