[C语言][LeetCode][203]Remove Linked List Elements

题目

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

标签

Linked List

难度

简单

分析

题目意思是给定一个单链表和一个value，删除链表里和value相同的节点，返回新的链表。我的做法是先找到要返回链表的头结点，然后遍历链表，如果遇到和value不相同的节点，则保存节点，否则跳过。

C代码实现

struct ListNode* removeElements(struct ListNode* head, int val) {    struct ListNode * p;    struct ListNode * q;    struct ListNode * ret;    if(!head)        return NULL;    p = head;    while(p && (p->val == val))     // find the head of the return list    {        p = p->next;    }    if(!p)        return NULL;    q = p;    ret = q;                                   // keep the first element of the return list    p = p->next;    while(p)    {        if(p->val != val)                 // if val is not equal the p->val, save it to the return list        {            q->next = p;            q = p;        }        p = p->next;    }    q->next =NULL;    return ret;}