Remove Linked List Elements

Remove Linked List Elements (leetcodelintcode)

Description
Remove all elements from a linked list of integers that have value val.

Example
Given 1-
>
2-
>
3-
>
3-
>
4-
>
5-
>
3, val = 3, you should return the list as 1-
>
2-
>
4-
>
5.

解题思路

考虑到链表头结点可能被删除，所以需要使用哨兵结点dummy node。

Java 实现

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

/**
     * 
@param
 head a ListNode
     * 
@param
 val an integer
     * 
@return
 a ListNode
     */
public
 ListNode 
removeElements
(ListNode head, 
int
 val)
{

if
 (head == 
null
) {

return
null
;
        }

        ListNode dummy = 
new
 ListNode(
0
);
        dummy.next = head;
        head = dummy;


while
 (head.next != 
null
) {

if
 (head.next.val == val) {
                head.next = head.next.next;
            } 
else
 {
                head = head.next;
            }
        }


return
 dummy.next;
    }
}