237. Delete Node in a Linked List

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.

 

Solution 1:

思路：把所有之后的节点都左移，然后删掉最后一个节点。麻烦了。

/**
 * 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) {
        ListNode copy=node;
        while(node!=null&&node.next!=null)
        {
            copy=node;
           node.val=node.next.val;
           node=node.next;
        }
        copy.next=null;
    }
}

Solution 2:

看了下disucssion，其实只要把右边的节点交换过来然后删掉右边的一个节点就可以了。满满都是套路啊

public void deleteNode(ListNode node) {
    node.val=node.next.val;
    node.next=node.next.next;
}