Pattern De-Duplication based on Subsequence Detection

[miles-grant-ibigroup]

Description:

Possibly a slightly overbuilt way to use subsequence detection to remove patterns that are simply a subsequence of another, larger pattern.

There are definitely a few optimizations possible here. I am looking for feedback on some of these algorithms and if there's a way to make the more efficient.

I believe this should be possible in O(n) time, right now it's O(n^2) although reversing the sorted array should help remove the most useless of these comparisons

[amy-corson-ibigroup]

What do we think of this possible cleanup? Approving because this does work as-is!!

[amy-corson-ibigroup]

What about

Suggested change

	.filter((pattern) => {
	// Compare to all other patterns TODO: make this beat O(n^2)
	return !patternsSortedByLength.find((p) => {
	// Don't compare against ourself
	if (p.id === pattern.id) return false
	// If our pattern is longer, it's not a subset
	if (p.stops.length < pattern.stops.length) return false
	return isValidSubsequence(
	p.stops.map((s) => s.id),
	pattern.stops.map((s) => s.id)
	)
	})
	})
	.filter((pattern, patternIndex) => {
	// Compare to all other patterns larger than the current pattern
	return !patternsSortedByLength.find((p, pIndex) => {
	if (pIndex >= patternIndex) return false
	return isValidSubsequence(
	p.stops.map((s) => s.id),
	pattern.stops.map((s) => s.id)
	)
	})
	})

You're already sorting by length so checking anything above a certain index number feels like a waste of time, and you could remove the if (p.id === pattern.id) block because p and pattern should have the same index. This gets the same result for 1-line patterns but might need more testing!!

[miles-grant-ibigroup]

I think we need to check the pattern id because the indexes don't always line up. I agree the length check is not required but to do that we need to start checking the second array at the right index and that logic is currently not present

[daniel-heppner-ibigroup]

Neat algorithm, I don't see a way to make it faster immediately. Good start!