【LeetCode】203. Remove Linked List Elements

Remove Linked List Elements

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

Credits:
Special thanks to @mithmatt for adding this problem and creating all test cases.

 

遇到val则删除，否则继续前进，直到链表结尾。

/**
 * 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* newhead = new ListNode(-1);
        newhead->next = head;
        ListNode* pre = newhead;
        ListNode* cur = head;
        while(cur != NULL)
        {
            if(cur->val == val)
            {
                cur = cur->next;
                pre->next = cur;
            }
            else
            {
                pre = cur;
                cur = cur->next;
            }
        }
        return newhead->next;
    }
};