LeetCode 92. Reverse Linked List II

代码：

class Solution
{
public:
ListNode *reverseBetween(ListNode *head, int m, int n)
{
if (head==NULL || m==n)
{
return head;
}

ListNode *cut=head, *cur=head;

for (int i = 1; i < m; ++ i)
{
cut = cur;
cur = cur->next;
}
ListNode* prev = cur;
cur = cur->next;
for (int i = 0; i < n-m; ++ i)
{
ListNode* next = cur->next;
cur->next = prev;
prev = cur;
cur = next;
}

if (m == 1)
{
head->next = cur;
return prev;
} else
{
cut->next->next = cur;
cut->next = prev;
return head;
}
}
};