移除链表元素

删除链表中等于给定值 val 的所有节点。

 

/**
 * 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 == NULL){
            return head;
        }
        while(head != NULL and head->val == val){
            head = head->next;
        }
        if(head == NULL || head->next == NULL){
            return head;
        }
        else{
            ListNode *s = head;
            ListNode *f = s->next;
            while(f != NULL){
                if(f->val == val){
                    s->next = f->next;
                    f = s->next;
                    continue;
                }
                s = s->next;
                f = f->next;
            }
            return head;
        }
    }
};