class Solution {
public:
    ListNode* oddEvenList(ListNode* head) {
        if(head==NULL || head->next==NULL){
            return head;
        }
        ListNode* odd=head;
        ListNode* even=head->next;
        ListNode* evenHead=head->next;
        while(odd->next!=NULL && odd->next->next!=NULL){
            odd->next=odd->next->next;
            odd=odd->next;
        }
        while(even!=NULL && even->next!=NULL){
            even->next=even->next->next;
            even=even->next;
        }
        odd->next=evenHead;
        return head;
    }
};

Error: AddressSanitizer: heap-use-after-free on address

{1,2,3,4,5,6,7,8}================>{1,3,3,5,7,2,4,6}