[LeeetCode] 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

删除链表中指定值，找到其前一个节点即可，将 next 指向下一个节点即可。

设置一个哑节点来防止头节点被删除造成无法返回新链表。

/**
 * 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 == nullptr)
            return 0;
        ListNode* dummy = new ListNode(0);
        dummy->next = head;
        ListNode* cur = dummy;
        while (cur->next) {
            if (cur->next->val == val) {
                cur->next = cur->next->next;
            }
            else {
                cur = cur->next;
            }
        }
        return dummy->next;
    }
};
// 26 ms