203. 移除链表元素

Posted 2021-02-21 jianzha

package 链表;

/**
 * https://leetcode-cn.com/problems/remove-linked-list-elements/
 * 203. 移除链表元素
 * <p>
 * 解题思路 ：使用哨兵
 */
public class _203_Remove_Linked_List_Elements {


    public class ListNode {
        int val;
        ListNode next;

        ListNode(int x) {
            val = x;
        }
    }

    class Solution {
        public ListNode removeElements(ListNode head, int val) {
            // 新建个节点，防止第一个节点就是要被移除的节点
            ListNode sentinel = new ListNode(0);
            sentinel.next = head;
            // 前一个节点
            ListNode prev = sentinel;
            // 后一个节点
            ListNode curr = head;
            while (curr != null) {
                if (curr.val == val) {
                    prev.next = curr.next;
                } else {
                    prev = curr;
                }
                curr = curr.next;
            }
            return sentinel.next;
        }
    }
}