37 lines
815 B
Java
37 lines
815 B
Java
# 24. 反转链表
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[NowCoder](https://www.nowcoder.com/practice/75e878df47f24fdc9dc3e400ec6058ca?tpId=13&tqId=11168&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
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## 解题思路
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### 递归
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```java
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public ListNode ReverseList(ListNode head) {
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if (head == null || head.next == null)
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return head;
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ListNode next = head.next;
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head.next = null;
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ListNode newHead = ReverseList(next);
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next.next = head;
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return newHead;
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}
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```
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### 迭代
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使用头插法。
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```java
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public ListNode ReverseList(ListNode head) {
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ListNode newList = new ListNode(-1);
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while (head != null) {
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ListNode next = head.next;
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head.next = newList.next;
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newList.next = head;
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head = next;
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}
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return newList.next;
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}
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```
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