LetCode 92. 反转链表 II

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本文介绍了一种反转链表中指定区间[m, n]的方法，并提供了一个C++实现示例。该方法通过创建辅助节点和使用迭代的方式实现了链表区间的反转。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* reverseBetween(ListNode* head, int m, int n) {
        if (head == NULL)
            return head;
        ListNode *voidptr = new ListNode(0);
        voidptr->next = head;
        ListNode *m_node = voidptr;
        ListNode *n_node = voidptr;
        ListNode *cur_node = head;
        ListNode *first;
        ListNode *last;
        int index = 1;
        while(index <= n && cur_node != NULL){
            if (index == m - 1)
                m_node = cur_node;
            if (index == n)
                n_node = cur_node;
            if (m <= index && index <= n){
                int val = cur_node->val;
                ListNode* tmp = new ListNode(val);
                if (m == index)
                    first = tmp, last = first;
                else
                    tmp->next = last, last = tmp;
            }
            cur_node = cur_node->next;
            ++index;
        }
        m_node->next = last;
        first->next = n_node->next;
        return voidptr->next;
    }
};

static int x=[](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();