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

Given linked list – head = [4,5,1,9], which looks like following:

4 -> 5 -> 1 -> 9

Example 1:

Input: head = [4,5,1,9], node = 5
Output: [4,1,9]
Explanation: You are given the second node with value 5, the linked list
             should become 4 -> 1 -> 9 after calling your function.
 

Example 2:

Input: head = [4,5,1,9], node = 1
Output: [4,5,9]
Explanation: You are given the third node with value 1, the linked list
             should become 4 -> 5 -> 9 after calling your function.

Note:

• The linked list will have at least two elements.
• All of the nodes’ values will be unique.
• The given node will not be the tail and it will always be a valid node of the linked list.
• Do not return anything from your function.

題意：要求在單鏈表中刪除一個節點（這個節點不會是尾節點，並且連結串列的節點數至少為2）；

解法：想到刪除連結串列的節點我們想到的應當是遍歷連結串列，找到那個節點後將前一個節點的指標指向此指定節點的後一個節點，之後刪除這個節點；但其實因為節點僅包含了一個節點值和一個後繼，我們完全可以將下一個節點的值賦予這個節點，並且此節點的後繼等於下一個節點的後繼；（但是，這一題其實並沒有真的釋放那個節點）；

Java

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