Java [Leetcode 203]Remove Linked List Elements

Posted 2020-06-13

题目描述:

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

Example
Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6
Return: 1 --> 2 --> 3 --> 4 --> 5

解题思路：

链表操作。

代码如下：

/**
 * Definition for singly-linked list.
 * public class ListNode {
 *     int val;
 *     ListNode next;
 *     ListNode(int x) { val = x; }
 * }
 */
public class Solution {
    public ListNode removeElements(ListNode head, int val) {
    	ListNode res = new ListNode(0);
    	res.next = head;
    	ListNode point = head, pre = res;

    	while(point != null) {
    		if(point.val == val) {
    			if(point.next != null) {
    				point.val = point.next.val;
    				point.next = point.next.next;
    			} else {
    				point = null;
    				pre.next = null;
    			}
    		} else {
    			point = point.next;
    			pre = pre.next;
    		}
    	}	
    	return res.next;
    }
}