[LeetCode] Problem 206 - Reverse Linked List

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Reverse a singly linked list.

Example

Input: 1->2->3->4->5->NULL

Output: 5->4->3->2->1->NULL

Follow up

A linked list can be reversed either iteratively or recursively. Could you implement both?

Code

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public class ListNode {
    int val;
    ListNode next;
    ListNode(int x) { val = x; }
}
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public ListNode reverseList(ListNode head) {
    ListNode prev = null;
    ListNode cur = head;

    while (cur != null) {
        ListNode next = cur.next;
        cur.next = prev;
        prev = cur;
        cur = next;
    }

    return prev;
}