New tasks

2. Add Two Numbers/2. Add Two Numbers.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <RootNamespace>_2._Add_Two_Numbers</RootNamespace>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

2. Add Two Numbers/ListNode.cs

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+namespace _2._Add_Two_Numbers;
+
+public class ListNode {
+    public int val;
+    public ListNode? next;
+    public ListNode(int val=0, ListNode? next=null) {
+        this.val = val;
+        this.next = next;
+    }
+}

2. Add Two Numbers/Program.cs

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+namespace _2._Add_Two_Numbers;
+
+internal class Program
+{
+    static void Main(string[] args)
+    {
+        
+    }
+}

2. Add Two Numbers/Solution.cs

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+namespace _2._Add_Two_Numbers;
+
+public class Solution {
+    public ListNode AddTwoNumbers(ListNode? l1, ListNode? l2)
+    {
+        ListNode? answer = null;
+        ListNode? answerEnd = answer;
+        int toNext = 0;
+        while (l1!=null || l2!=null)
+        {
+            int sum = 0;
+            if (l1 != null)
+            {
+                sum += l1.val;
+                l1 = l1.next;
+            }
+            if (l2 != null)
+            {
+                sum += l2.val;
+                l2 = l2.next;
+            }
+
+            sum += toNext;
+            toNext = sum / 10;
+            sum %= 10;
+            ListNode item = new ListNode(sum);
+            if (answer == null)
+                answer = answerEnd = item;
+            else
+            {
+                answerEnd.next = item;
+                answerEnd = item;
+            }
+        }
+
+        if (toNext != 0)
+            answerEnd.next = new ListNode(toNext);
+        return answer;
+    }
+}