Leetcode Solution for "Remove Linked List Elements" problem in CPP

remove_val_from_SLL.cpp

class Solution {
public:
    ListNode* removeElements(ListNode* head, int val) {
        struct ListNode *p = head, *q=NULL;
        if(head==NULL){
            return head;
        }
            while(p->val == val && p->next!=NULL){
                p=p->next;
                head = p;
            }
        if(p->val==val){
            return NULL;
        }
            while(p->next!=NULL){
                q=p;
                p=p->next;
                if(p->val == val){
                    while(p->next != NULL && p->next->val == val){
                        p=p->next;
                    }
                    q->next = p->next;
                }
            }
        return head;
    }
};