题目连接
https://leetcode.com/problems/remove-linked-list-elements/
Remove Linked List Elements
Description
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
/**
* 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) {
if (!head) return NULL;
ListNode *p = head, *x = NULL;
if (p->val == val) {
while (p->next && p->val == val) {
x = p;
p = x->next;
delete x;
}
head = p;
}
while (p && p->next) {
while (p->next && p->next->val == val) {
x = p->next;
p->next = x->next;
delete x;
}
p = p->next;
}
return (!head->next && head->val == val) ? NULL : head;
}
};