算法--链表指定值清除

import java.util.*;

/*

public class ListNode {

    int val;

    ListNode next = null;

    ListNode(int val) {

        this.val = val;

    }

}*/

public class ClearValue {

    public ListNode clear(ListNode head, int val) {

        while (head != null) {

            if (head.val != val) {

                break;

            }

            head = head.next;

        }

        ListNode pre = head;

        ListNode cur = head;

        while (cur != null) {

            if (cur.val == val) {

                pre.next = cur.next;

            } else {

                pre = cur;

            }

            cur = cur.next;

        }

        return head;

    }

}