How does Google Yandex find a site in a split second by the “quoted line”?

Question

Search engines

It's okay to find it by keywords, it's still clear.
But how do they find ANY string in trillions of gigabytes of characters, how is that?

Answer 1

Nodal "tree", where each node is one word (maybe bi / tri-gram).
The number of points scored (length of the path) at the time of passing through the links and the presence of certain IDs accurately determines (highlights) the sites that contain the quoted string.
(and, of course, the search is conducted only on pre-indexed data)

Answer 2

They found "any string" long before this second. And then they simply optimized the data on their servers. It can be said that they copied the Internet (although in fact only part of the Internet).