92. Reverse Linked List II

局部反转：

/**
 * 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) {
        ListNode* newhead=(ListNode*)malloc(sizeof(ListNode));
        newhead->next=head;
        ListNode* start=newhead;
        int flag=m;
        while(m>1)
        {
            m--;
            start=start->next;
        }
        
        ListNode *move=start->next;
        ListNode *end=move;
        int temp=1;
        while(n>=flag)
        {
            n--;
            if(temp)
            {
                temp--;
                move=move->next;
            }
            else
            {
                end->next=move->next;
                move->next=start->next;
                start->next=move;
                move=end->next;
            }      
            
          
        }
        
        return newhead->next;       
    }
};