题解 | #链表内指定区间反转#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 *	ListNode(int x) : val(x), next(nullptr) {}
 * };
 */
#include <exception>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param head ListNode类 
     * @param m int整型 
     * @param n int整型 
     * @return ListNode类
     */
    ListNode* reverseBetween(ListNode* head, int m, int n) {
        ListNode* res = new ListNode(-1);
        res -> next = head;
        // write code here
        ListNode* pre = res;
        ListNode* cur = head;
        for(int i = 1; i < m; i++){
            pre = cur;
            cur = cur -> next;
        }
        for(int i = m; i < n; i++){
            ListNode* temp = cur -> next;
            cur -> next = temp -> next;
            temp -> next = pre -> next;
            pre -> next = temp;
        }
        return res -> next;
    }
};