leetcode，我觉得没啥问题呀，反转链表，为什么会报错

Question

问题遇到的现象和发生背景

https://leetcode-cn.com/problems/reverse-linked-list-ii/

问题相关代码，请勿粘贴截图

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    void reverse(ListNode* head){
        ListNode* reverse = nullptr;
        ListNode* p = head;
        ListNode* tmp;
        while(p!=nullptr){
            tmp = p->next;
            p->next = reverse;
            reverse = p;
            p = tmp;
        }
    }
public:
    ListNode* reverseBetween(ListNode* head, int left, int right) {
        while(head == nullptr||head->next == nullptr)
                return head;
        ListNode* dummy = new ListNode(0,head);
        ListNode* lefthead = dummy;
        ListNode* leftt;
        for(int j = 0;j<left-1;j++){
            lefthead = lefthead->next;
        }
        leftt = lefthead->next;

        ListNode* righthead = dummy;
        ListNode* rightt;
        for(int i = 0;i<right;i++)
            righthead = righthead->next;
        rightt = righthead->next;

        lefthead->next = nullptr;
        righthead->next = nullptr;
        reverse(leftt);

        lefthead->next = righthead;
        leftt->next = righthead;
        return dummy->next;
    }
};

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果

Answer 1

错误不少不好一一指出，建议学会调试，另外考虑问题要全面，