Problem
Reverse a linked list from position m to n. Do it in-place and in one-pass.
For example:
Given
Given
1->2->3->4->5->NULL
, m = 2 and n = 4,
return
1->4->3->2->5->NULL
.
Note:
Given m, n satisfy the following condition:
1 ≤ m ≤ n ≤ length of list.
Given m, n satisfy the following condition:
1 ≤ m ≤ n ≤ length of list.
Code
ListNode *rb_r(ListNode *node,int count,int n, ListNode **front,ListNode *rear,ListNode **head) { if(count == n + 1){ *front = node; return rear; } ListNode *prev = rb_r(node->next,count + 1,n,front,rear,head); if(!prev){ *head = node; } else{ prev->next = node; } return node; } ListNode *reverseBetween(ListNode *head, int m, int n) { // IMPORTANT: Please reset any member data you declared, as // the same Solution instance will be reused for each test case. ListNode *rear = 0; ListNode *node = head; if(m > 1){ int count = 1; rear = head; while(count < m - 1){ rear = rear->next; ++count; } node = rear->next; } ListNode *front; ListNode *prev = rb_r(node,m,n,&front,rear,&head); prev->next = front; return head; }
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