剑指OfferII 021. 删除链表的倒数第n个结点

Author: BGMer7

src/com/gatsby/offerII/_21RemoveNthFromEnd.java

@@ -0,0 +1,34 @@
+package com.gatsby.offerII;
+
+import com.gatsby.ListNode;
+
+/**
+ * @ClassName: _21RemoveNthFromEnd
+ * @Description: 剑指 Offer II 021. 删除链表的倒数第 n 个结点
+ * <p>
+ * 1 -> 2 -> 3 -> 4 -> 5
+ * @author: Gatsby
+ * @date: 2022/7/14 13:38
+ */
+
+public class _21RemoveNthFromEnd {
+    public ListNode removeNthFromEnd(ListNode head, int n) {
+        ListNode dummy = new ListNode(-1);
+        dummy.next = head;
+        ListNode fast = dummy;
+        ListNode slow = dummy;
+        while (n-- != 0) {
+            fast = fast.next;
+        }
+
+        while (fast != null && fast.next != null) {
+            fast = fast.next;
+            slow = slow.next;
+        }
+
+        slow.next = slow.next.next;
+        return dummy.next;
+    }
+}
+
+