Remove Linked List Elements

来源：互联网发布：linux 添加组编辑：程序博客网时间：2024/06/05 14:16

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

1、因为可能有表头是val的情况，设置辅助头结点 Head->next=head,

2、直接在链表中考虑，头结点移动，直到不是val时再进行判断

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

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

0 0