Delete a node, only give access to that node.

Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.

Supposed the linked list is 

1 -> 2 -> 3 -> 4

 and you are given the third node with value 

3

,
the linked list should become 

1 -> 2 -> 4

 after calling your function.

思路：Only access to that node, we can copy the value of next node to that node, and point to the next.next;

/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
public class Solution {
public void deleteNode(ListNode node) {
if(node == null || node.next == null) {
return;
}
ListNode next = node.next;
node.val = next.val;
node.next = next.next;
return;
}
}