doc: 2025-10-24打卡

92.reverse-linked-list-ii.java

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+/*
+ * @lc app=leetcode id=92 lang=java
+ *
+ * [92] Reverse Linked List II
+ */
+
+// @lc code=start
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    /**
+     * 链表逆序：头插法
+     * @param head
+     * @param left
+     * @param right
+     * @return
+     */
+    public ListNode reverseBetween(ListNode head, int left, int right) {
+        ListNode dummy = new ListNode(0);
+        dummy.next = head;
+        ListNode prev = dummy;
+        for(int i = 0; i< left-1; i++) {
+            prev = prev.next;
+        }
+        ListNode cur = prev.next;
+        ListNode tail = cur, tmp;
+        for(int i = 0; i < right-left; i++) {
+            cur = tail.next;
+            tail.next = cur.next;
+            cur.next = prev.next;
+            prev.next = cur;
+        }
+        return dummy.next;
+    }
+}
+// @lc code=end
+