206.png
public class ListNode {
int val;
ListNode next;
ListNode(int x) { val = x; }
}
public ListNode reverseList(ListNode head) {
ListNode pre = null;
ListNode cur = head;
while(cur != null){
ListNode next = cur.next;
cur.next = pre;
pre = cur;
cur = next;
}
return pre;
}
