题解 | #链表内指定区间反转#

/**
 * struct ListNode {
 *	int val;
 *	struct ListNode *next;
 * };
 */

#include <list>
class Solution {
public:
    /**
     * 
     * @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) {
        // write code here
        ListNode* pre = new ListNode(0);
        ListNode* cur = head;
        ListNode* left = nullptr;
        ListNode* right = nullptr;
        ListNode* temp = nullptr;
        pre->next = cur;
        int i;
        if(head == nullptr)
        return nullptr;
        if(m == n)
        return head;
        if(m>n)
        return nullptr;
     
        for(i=1;i<m;i++)
        {
            pre = cur;
            cur = cur->next;
        }
        left = cur;
        right = left ->next;
        for(i=m;i<n;i++)
        {
            temp = right->next;
            right->next = left;
            left = right;
            right = temp;
        }
        pre->next = left;
        cur->next = right;
        if(m>1)
        {
            return head;
        }
        else {
            return left;
        }

    }
};