Update solution 0445

Author: halfrost

website/content/ChapterFour/0400~0499/0445.Add-Two-Numbers-II.md

@@ -32,6 +32,22 @@ Output: 7 -> 8 -> 0 -> 7
 
 package leetcode
 
+/**
+ * Definition for singly-linked list.
+ * type ListNode struct {
+ *     Val int
+ *     Next *ListNode
+ * }
+ */
+package leetcode
+
+import (
+	"github.com/halfrost/LeetCode-Go/structures"
+)
+
+// ListNode define
+type ListNode = structures.ListNode
+
 /**
  * Definition for singly-linked list.
  * type ListNode struct {
@@ -93,6 +109,75 @@ func getLength(l *ListNode) int {
 	return count
 }
 
+func addTwoNumbers1(l1 *ListNode, l2 *ListNode) *ListNode {
+	reservedL1 := reverseList(l1)
+	reservedL2 := reverseList(l2)
+
+	dummyHead := &ListNode{}
+	head := dummyHead
+	carry := 0
+	for reservedL1 != nil || reservedL2 != nil || carry > 0 {
+		val := carry
+		if reservedL1 != nil {
+			val = reservedL1.Val + val
+			reservedL1 = reservedL1.Next
+		}
+		if reservedL2 != nil {
+			val = reservedL2.Val + val
+			reservedL2 = reservedL2.Next
+		}
+		carry = val / 10
+		head.Next = &ListNode{Val: val % 10}
+		head = head.Next
+	}
+	return reverseList(dummyHead.Next)
+}
+
+func reverseList(head *ListNode) *ListNode {
+	var prev *ListNode
+	for head != nil {
+		tmp := head.Next
+		head.Next = prev
+
+		prev = head
+		head = tmp
+	}
+	return prev
+}
+
+func addTwoNumbers(l1 *ListNode, l2 *ListNode) *ListNode {
+	stack1 := pushStack(l1)
+	stack2 := pushStack(l2)
+
+	dummyHead := &ListNode{}
+	head := dummyHead
+	carry := 0
+	for len(stack1) > 0 || len(stack2) > 0 || carry > 0 {
+		val := carry
+		if len(stack1) > 0 {
+			val = val + stack1[len(stack1)-1]
+			stack1 = stack1[:len(stack1)-1]
+		}
+		if len(stack2) > 0 {
+			val = val + stack2[len(stack2)-1]
+			stack2 = stack2[:len(stack2)-1]
+		}
+		carry = val / 10
+		tmp := head.Next
+		head.Next = &ListNode{Val: val % 10, Next: tmp}
+	}
+	return dummyHead.Next
+}
+
+func pushStack(l *ListNode) []int {
+	var stack []int
+	for l != nil {
+		stack = append(stack, l.Val)
+		l = l.Next
+	}
+	return stack
+}
+
 ```