does `in` cause the runtime of the program to become as if it were 2 for loops O(n2)?

# getting-started

[oday]

does in cause the runtime of the program to become as if it were 2 for loops O(n2)?

[Tobias Berger]

in in this case is just syntactic sugar for contains, so line 7 is the same as if (values.contains(difference)) {. What happens inside of the contains-Function depends on the map implementation (here a LinkedHashMap)

[oday]

so map access is O(1)

[oday]

so this is O(n)

[nanodeath]

so because this is Kotlin, they should be basically the same, but normally (e.g. Java) contains and .get(...) != null can be different because values can be null. but because it's Kotlin, they're basically equivalent

[nanodeath]

also btw I'd use the infix to instead of Pair...usually looks nicer

[nanodeath]

also you might say values[difference]?.let { return index to it } (or something like that), as that'll save you the trouble of doing the lookup in values twice