Add new linked list exercise

golang/2.go

@@ -0,0 +1,41 @@
+package golang
+
+/**
+ * Definition for singly-linked list.
+ * type ListNode2 struct {
+ *     Val int
+ *     Next *ListNode2
+ * }
+ */
+
+type ListNode2 struct {
+	Val  int
+	Next *ListNode2
+}
+
+func addTwoNumbers(l1 *ListNode2, l2 *ListNode2) *ListNode2 {
+	carry := 0
+	head := &ListNode2{Val: 0}
+	current := head
+
+	for l1 != nil || l2 != nil || carry > 0 {
+		total := carry
+
+		if l1 != nil {
+			total += l1.Val
+			l1 = l1.Next
+		}
+
+		if l2 != nil {
+			total += l2.Val
+			l2 = l2.Next
+		}
+
+		carry = total / 10
+		(*current).Next = &ListNode2{Val: total % 10}
+		current = current.Next
+	}
+
+	return head.Next
+
+}

golang/2_test.go

@@ -0,0 +1,36 @@
+package golang
+
+import "testing"
+import "slices"
+
+func TestFirstAddTwoNumbers(t *testing.T) {
+
+	l1 := &ListNode2{
+		Val: 2,
+		Next: &ListNode2{
+			Val:  4,
+			Next: &ListNode2{Val: 3},
+		},
+	}
+	l2 := &ListNode2{
+		Val: 5,
+		Next: &ListNode2{
+			Val:  6,
+			Next: &ListNode2{Val: 4},
+		},
+	}
+
+	result := addTwoNumbers(l1, l2)
+	s := []int{}
+
+	for result != nil {
+		s = append(s, result.Val)
+		result = result.Next
+	}
+
+	expected := []int{7, 0, 8}
+
+	if !slices.Equal(expected, s) {
+		t.Fatalf(`Expected %v but received %v`, expected, s)
+	}
+}

golang/README.md

@@ -1,5 +1,6 @@
 | Problem Number | Tag                            | URL                                                                                  |
 | -------------- | ------------------------------ | ------------------------------------------------------------------------------------ |
+| 2.go           | Linked List                    | https://leetcode.com/problems/add-two-numbers/                                       |
 | 888.go         | Hash table                     | https://leetcode.com/problems/fair-candy-swap                                        |
 | 1290.go        | Linked List / Bit manipulation | https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer      |
 | 1539.go        | Binary Search                  | https://leetcode.com/problems/kth-missing-positive-number/                           |