24.8.21 LeetCode Hot100 linkedList

src/main/java/com/cool/hot100/linkedlist/Num206.java

@@ -1,5 +1,7 @@
 package com.cool.hot100.linkedlist;
 
+import org.junit.Test;
+
 public class Num206 {
 
     /**
@@ -11,7 +13,25 @@ public class Num206 {
      */
 
     public ListNode reverseList(ListNode head) {
-
+        if(head==null) return null;
+        ListNode node=head;
+        ListNode upNode=null;
+        while (node!=null){
+            ListNode nextNode=node.next;
+            node.next=upNode;
+            upNode=node;
+            node=nextNode;
+        }
+        return upNode;
+    }
+    @Test
+    public void test(){
+        ListNode node=new ListNode(5,null);
+        ListNode node1=new ListNode(4,node);
+        ListNode node2=new ListNode(3,node1);
+        ListNode node3=new ListNode(2,node2);
+        ListNode node4=new ListNode(1,node3);
+        reverseList(node4);
     }
 
 }

src/main/java/com/cool/hot100/linkedlist/Num234.java

@@ -0,0 +1,33 @@
+package com.cool.hot100.linkedlist;
+
+public class Num234 {
+
+    /**
+     * DayNumber 2
+     * Date 2024/8/20
+     * Hard 1
+     *
+     * @return
+     */
+    public ListNode node;
+
+    public boolean isPalindrome(ListNode head) {
+        node = head;
+        return reNodeCheck(head);
+    }
+
+    //递归反向对比
+    public boolean reNodeCheck(ListNode node){
+        if (node!=null){
+            if(!reNodeCheck(node.next)){
+                return false;
+            }
+            if(node.val!=this.node.val){
+                return false;
+            }
+            this.node=this.node.next;
+        }
+        return true;
+    }
+
+}