[Leetcode]237. Delete Node in a Linked List -David_Lin

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.

 

法一：思路是：从node 节点开始，把后面节点的值赋给前面的节点，直到到表尾；

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

 

法二：将要删除节点后一个节点的值赋给要删除的节点，然后删除后一个节点。

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