Add Two Numbers
You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
class ListNode(var value: Int, var next: ListNode = null) {
def +(that: ListNode): ListNode = {
if (that == null) this
else {
val sum = this.value + that.value
var next = new ListNode(sum / 10) + this.next + that.next
if (next.value == 0 && next.next == null) next = null
new ListNode(sum % 10, next)
}
}
}
/**
* wrapper function
* @param l1
* @param l2
* @return
*/
def addTwoNumbers(l1: ListNode, l2: ListNode): ListNode = {
if (l1 != null && l2 != null) l1 + l2
else if (l1 == null) l2
else l1
}
/**
* utility function
* @param nums
* @return
*/
def createLinkedList(nums: Array[Int]): ListNode = {
nums
.map(num => new ListNode(num))
.foldRight[ListNode](null)((l: ListNode, r: ListNode) => {
l.next = r; l
})
}
/**
* utility function
* @param n
*/
def printLinkedList(n: ListNode): Unit = {
var head = n
while (head != null) {
println(head.value)
head = head.next
}
}
var n1 = createLinkedList(Array(0))
var n2 = createLinkedList(Array(1))
printLinkedList(addTwoNumbers(n1, n2))
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