diff --git a/src/leecode/122.买卖股票的最佳时机-ii.java b/src/leecode/122.买卖股票的最佳时机-ii.java
index 0d72364..da01235 100644
--- a/src/leecode/122.买卖股票的最佳时机-ii.java
+++ b/src/leecode/122.买卖股票的最佳时机-ii.java
@@ -5,7 +5,7 @@ package leecode;/*
  */
 
 // @lc code=start
-class Solution {
+class No122 {
     //贪心算法
     public int maxProfit(int[] prices) {
         int len = prices.length;
@@ -94,7 +94,7 @@ class Solution {
 
     public static void main(String[] args) {
         int[] price = new int[]{1, 2, 3};
-        Solution solution = new Solution();
+        No122 solution = new No122();
         System.out.println(solution.maxProfit(price));
     }
 
diff --git a/src/leecode/19.删除链表的倒数第-n-个结点.java b/src/leecode/19.删除链表的倒数第-n-个结点.java
new file mode 100644
index 0000000..b8b8b1b
--- /dev/null
+++ b/src/leecode/19.删除链表的倒数第-n-个结点.java
@@ -0,0 +1,39 @@
+package leecode;/*
+ * @lc app=leetcode.cn id=19 lang=java
+ *
+ * [19] 删除链表的倒数第 N 个结点
+ */
+
+// @lc code=start
+
+//  Definition for singly-linked list.
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+class Solution {
+    public ListNode removeNthFromEnd(ListNode head, int n) {
+        List<ListNode> cache =new ArrayList<>();
+        ListNode ret = head;
+        while (head != null) {
+            cache.add(head);
+            head = head.next;
+        }
+        if (n == cache.size()) {
+            return ret.next;
+        }
+        cache.get(cache.size() - n - 1).next = n == 1 ? null : cache.get(cache.size() - n + 1);
+        return ret;
+    }
+
+//      private static class ListNode {
+//          int val;
+//          ListNode next;
+//          ListNode() {}
+//          ListNode(int val) { this.val = val; }
+//          ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+//      }
+}
+// @lc code=end
+
diff --git a/src/leecode/python/14.最长公共前缀.py b/src/leecode/python/14.最长公共前缀.py
index 92c70dd..6db47d8 100644
--- a/src/leecode/python/14.最长公共前缀.py
+++ b/src/leecode/python/14.最长公共前缀.py
@@ -9,7 +9,7 @@
 from typing import List
 
 
-class Solution:
+class leecode.Solution:
     def longestCommonPrefix(self, strs: List[str]) -> str:
         # 遍历
         # if not strs:
diff --git a/src/leecode/python/21.合并两个有序链表.py b/src/leecode/python/21.合并两个有序链表.py
index 69c4396..7759f63 100644
--- a/src/leecode/python/21.合并两个有序链表.py
+++ b/src/leecode/python/21.合并两个有序链表.py
@@ -15,7 +15,7 @@ class ListNode:
         self.next = next
 
 
-class Solution:
+class leecode.Solution:
     def mergeTwoLists(self, list1: Optional[ListNode], list2: Optional[ListNode]) -> Optional[ListNode]:
         if not list1:
             return list2  # 终止条件，直到两个链表都空
@@ -29,5 +29,5 @@ class Solution:
             return list2
 
 
-sol = Solution()
+sol = leecode.Solution()
 # @lc code=end
diff --git a/src/leecode/python/9.回文数.py b/src/leecode/python/9.回文数.py
index 6e500ae..049188f 100644
--- a/src/leecode/python/9.回文数.py
+++ b/src/leecode/python/9.回文数.py
@@ -13,7 +13,7 @@
 # 奇数位 121
 # 12 1
 # 1  12
-class Solution:
+class leecode.Solution:
     def isPalindrome(self, x: int) -> bool:
        if x < 0 or (x % 10 == 0 and x != 0):
            return False