Remove Linked List Elements -- leetcode

Posted 2020-09-18 cxchanpin

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) {
        ListNode fake(0);
        fake.next = head;
        ListNode *p = &fake;
        ListNode *q = head;
        while (q) {
            if (q->val != val) {
                p = q;
                q = q->next;
            }
            else {
                p->next = q->next;
                delete q;
                q = p->next;
            }
        }
        return fake.next;
    }
};