链表 - Remove Linked List Elements
Remove Linked List Elements
描述:
Remove all elements from a linked list of integers that have value val.从一个链表中删除所有指定元素值的整数
Example
Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6
Return: 1 --> 2 --> 3 --> 4 --> 5
思路:
需要保证头指针的准确,有可能前面连续三个 四个 都是指定要删除的数值,这个个数是不确定的
算法:
/**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode(int x) { val = x; }
* }
*/
class Solution {
public ListNode removeElements(ListNode head, int val) {
if(head == null){
return null;
}
//为了确保head的准确
while (head.val == val){
if(head.next != null){
head = head.next;
}else {
return null;
}
}
ListNode before = head;
if(head.next != null){
ListNode target = head.next;
while (target != null){
if(target.val == val){
before.next = target.next;
target = before.next;
}else {
before = target;
target = before.next;
}
}
}
return head;
}
}