203. Remove Linked List Elements

題目原文

Remove all elements from a linked list of integers that have value val.

Example:

Input:  1->2->6->3->4->5->6, val = 6
Output: 1->2->3->4->5

解題思路

程式解答

class Solution 
{
public:
    ListNode* removeElements(ListNode* head, int val) 
    {
        ListNode *p = new ListNode(0);
        ListNode *ans = new ListNode(0);
        
        p->next = head;
        ans = p;
        
        while (head)
        {
            if (head->val == val)
            {
                p->next = p->next->next;
            }
            else
            {
                p->next = head;
                p = p->next;
            }
            head = head->next;
        }
        return ans->next;
    }
};