Inverted Index Search Algorithm

Question

Think about whether there are 10 million words that people searched on google. appropriate for each word you have a sorted list of all document identifiers. The list is as follows:

[Word 1]->[doc_i1,doc_j1,.....]
[Word 2]->[doc_i2,doc_j2,.....]
...
...
...
[Word N]->[doc_in,doc_jn,.....]

I am looking for an algorithm to search for 100 rare pairs of words. A rare pair of words is a pair of words that occur together (not necessarily adjacent) in exactly 1 document.

I am looking for something better than O (n ^ 2), if possible.

Answer 1

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