Commit f77677f

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parallelize day 21 part 2, for funsies

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Lines changed: 1 addition & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@`
`7`	`7`	`public class Part02 extends Problem {`
`8`	`8`
`9`	`9`	`public String solve(Stream<String> data) {`
`10`		`- System.out.println("TODO: This takes ~1.5 minutes to run, needs to be optimized");`
	`10`	`+ System.out.println("TODO: This takes ~1 minute to run, needs to be optimized");`
`11`	`11`	`return String.valueOf(ShipLock.calculateSumOfComplexities(data, 25));`
`12`	`12`	`}`
`13`	`13`

Lines changed: 7 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -43,9 +43,13 @@ record WithLength(PressSequence seq, long length) {`
`43`	`43`	`for (var navigator : navigators) {`
`44`	`44`	`var newPressSeqSet = new HashSet<PressSequence>();`
`45`	`45`	`// one to many results`
`46`		`- for (var pressSeq : pressSeqs) {`
`47`		`- var possiblePresses = navigator.getPossiblePressSequences(pressSeq);`
`48`		`- newPressSeqSet.addAll(possiblePresses);`
	`46`	`+`
	`47`	`+ // parallelization on my laptop w/ 16 virtual cores cuts runtime by 1/3, from 83s to 57s`
	`48`	`+ var results = pressSeqs.parallelStream()`
	`49`	`+ .map(navigator::getPossiblePressSequences)`
	`50`	`+ .toList();`
	`51`	`+ for(var result : results) {`
	`52`	`+ newPressSeqSet.addAll(result);`
`49`	`53`	`}`
`50`	`54`
`51`	`55`	`// calculate lengths just once, since it's a slightly expensive operation`

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