实现删除链表倒数第N个节点的功能

根据LeetCode19题的要求，实现了删除链表倒数第N个节点的功能。通过两个指针分别定位到第N个节点和链表头，当第一个指针移动到链表末尾时，第二个指针将跳过需要删除的节点，从而实现删除操作。提供了两个实现版本，分别在类Solution和类So中。

src/main/java/cn/whaifree/redo/redo_all_240721/LeetCode19.java

@@ -0,0 +1,56 @@
+package cn.whaifree.redo.redo_all_240721;
+
+import cn.whaifree.leetCode.model.ListNode;
+import org.junit.Test;
+
+/**
+ * @version 1.0
+ * @Author whai文海
+ * @Date 2024/8/9 21:20
+ * @注释
+ */
+public class LeetCode19 {
+    @Test
+    public void test() {
+
+//        new Solution().removeNthFromEnd(ListNode.listNodeFromArray(new int[]{1, 2, 3, 4, 5}), 2).printList();
+        new So().ListNoderemoveNthEromEnd(ListNode.listNodeFromArray(new int[]{1}), 1).printList();
+    }
+
+
+    class Solution {
+        public ListNode removeNthFromEnd(ListNode head, int n) {
+
+            ListNode pre = new ListNode(-1, head);
+            ListNode fast = pre;
+            ListNode slow = pre;
+            for (int i = 0; i < n; i++) {
+                fast = fast.next;
+            }
+
+            while (fast.next != null) {
+                fast = fast.next;
+                slow = slow.next;
+            }
+            slow.next = slow.next.next;
+            return pre.next;
+        }
+    }
+
+    class So {
+        public ListNode ListNoderemoveNthEromEnd(ListNode head, int n) {
+            ListNode first = new ListNode(0, head);
+            ListNode second = head;
+            for (int i = 0; i < n; i++) {
+                second = second.next;
+            }
+            while (second != null) {
+                first = first.next;
+                second = second.next;
+            }
+            first.next = first.next.next;
+            return head;
+
+        }
+    }
+}