解题思路:
(1)使用两个指针,一个前指针,一个当前指针
(2)注意删除节点是头结点的情况
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* removeElements(ListNode* head, int val) {
ListNode *pre = NULL,*curr = head;
while(curr) {
if (curr->val==val) { //删除元素为头结点
if (pre==NULL) head = head -> next;
else pre->next = curr->next;
curr = curr->next;
} else {
pre = curr;
curr = curr->next;
}
}
return head;
}
};