diff --git a/.idea/misc.xml b/.idea/misc.xml
index cb3160a..bcb5da6 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="23" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" project-jdk-name="openjdk-21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file
diff --git a/KtLeetcode.iml b/KtLeetcode.iml
index f889b2e..43dd653 100644
--- a/KtLeetcode.iml
+++ b/KtLeetcode.iml
@@ -8,7 +8,7 @@
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
       <sourceFolder url="file://$MODULE_DIR$/testResources" type="java-test-resource" />
     </content>
-    <orderEntry type="jdk" jdkName="23" jdkType="JavaSDK" />
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
   </component>
diff --git a/src/Main.kt b/src/Main.kt
index e62d862..911c4b0 100644
--- a/src/Main.kt
+++ b/src/Main.kt
@@ -2,6 +2,6 @@
 
 
 fun main() {
-
-
+    val t = Test3()
+    t.test()
 }
\ No newline at end of file
diff --git a/src/Test2.kt b/src/Test2.kt
index 9a13a3f..b672f85 100644
--- a/src/Test2.kt
+++ b/src/Test2.kt
@@ -4,25 +4,52 @@ class Test2 {
         var next: ListNode? = null
     }
 
-    fun addTwoNumbers(l1: ListNode?, l2: ListNode?): ListNode? {
-        val cf = false
-        val result = ListNode(1)
-        if (l1 != null) {
-            if (l2!=null){
+    fun getVal(l: ListNode?): Int {
+        return l?.`val` ?: 0
+    }
 
-            }
+    fun addTwoNumbers(l1: ListNode?, l2: ListNode?): ListNode? {
+        var cf = 0
+        var l1 = l1
+        var l2 = l2
+        val result: ListNode = ListNode(0)
+        var current: ListNode? = result
+
+
+        while (l1!=null||l2!=null){
+            val t = getVal(l1) + getVal(l2) + cf
+            cf = t/10
+            current?.next = ListNode(t%10)
+            current = current?.next
+            l1 = l1?.next
+            l2 = l2?.next
         }
-        return null
+
+        if (cf == 1){
+            current?.next = ListNode(1)
+        }
+
+        return result.next
     }
 
     fun test(){
-        val li1 = ListNode(2)
-        li1.next = ListNode(4)
-        li1.next!!.next = ListNode(3)
+        val li1 = ListNode(9)
+        li1.next = ListNode(9)
+        li1.next!!.next = ListNode(9)
+        li1.next!!.next!!.next = ListNode(9)
+
+
+        val li2 = ListNode(9)
+        li2.next = ListNode(9)
+        li2.next!!.next = ListNode(9)
+
+        var result = addTwoNumbers(li1,li2)
+        while (result!=null){
+            print(result.`val`)
+            print(",")
+            result=result.next
+        }
 
-        val li2 = ListNode(5)
-        li2.next = ListNode(6)
-        li2.next!!.next = ListNode(4)
 
     }
 }
\ No newline at end of file
diff --git a/src/Test3.kt b/src/Test3.kt
new file mode 100644
index 0000000..059a601
--- /dev/null
+++ b/src/Test3.kt
@@ -0,0 +1,10 @@
+class Test3 {
+
+    fun lengthOfLongestSubstring(s: String): Int {
+
+    }
+
+    fun test(){
+
+    }
+}
\ No newline at end of file