Build a stack from values
Updated
Building from a sequence means pushing each value in order. The first value is the bottom. The last value is the top. Empty input stays empty.
What to focus on
Left-to-right push: values [4, 1, 9] become stack [4, 1, 9] with top 9. If you needed the first value on top, you would push right-to-left. Say so.
Worked examples
three values
a = [4, 1, 9]- push 4, then 1, then 9
- top 9
Result: [4, 1, 9]
one value
a = [7]- one push
Result: [7]
empty
a = []- no pushes
Result: []
Try it
Write fromArray(values). values is a list of integers to push left to right. The last value becomes the top. Push each value in order. Empty input stays empty. [4, 1, 9] has top 9. [7] has top 7. [] stays [].
values is a list of integers. You may build an empty stack.