2. Add Two Numbers

gzc · Jan 29, 2022 · c18a8b0 · c18a8b0
1 parent be10ef7
commit c18a8b0
Showing 1 changed file with 19 additions and 0 deletions.
diff --git a/scala/0001-0010/Add Two Numbers.scala b/scala/0001-0010/Add Two Numbers.scala
@@ -0,0 +1,19 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode(_x: Int = 0, _next: ListNode = null) {
+ *   var next: ListNode = _next
+ *   var x: Int = _x
+ * }
+ */
+object Solution {
+    def addTwoNumbers(l1: ListNode, l2: ListNode): ListNode = {
+        def addTwoNumbersHelper(l1: ListNode, l2: ListNode, carry: Int): ListNode = {
+            if (l1 == null && l2 == null) if (carry == 0) null else ListNode(carry)
+            else if (l1 == null) addTwoNumbersHelper(ListNode(0), l2, carry)
+            else if (l2 == null) addTwoNumbersHelper(l1, ListNode(0), carry)
+            else ListNode((l1.x + l2.x + carry) % 10, addTwoNumbersHelper(l1.next, l2.next, (l1.x + l2.x + carry) / 10 ))
+        }
+
+        addTwoNumbersHelper(l1, l2, 0)
+    }
+}