flatten

Flatten

Nice to solve before

Instructions

Given list containing items (integer, lists, sub-lists) implement recursive function which returns list with all values flattened. This function mimics behaviour of Kotlin build in flatten method.

Challenge | Solution

Limitations

Don't use Kotlin build in flatten function.

Examples

flatten(listOf(1)) // 1

flatten(listOf(1), listOf(listOf(2))) // 1, 2

flatten(listOf(1), listOf(listOf(2), listOf(listOf(3)))) // 1, 2, 3

Hints

Hint 1

Use helper recursive function.