class Solution {
fun validateStackSequences(pushed: IntArray, popped: IntArray): Boolean {
var i = 0
var stack = LinkedList<Int>()
for (n in pushed) {
stack.addLast(n)
while (i < popped.size && popped[i] == stack.peekLast()) {
stack.removeLast()
i++
}
}
return stack.isEmpty()
}
}