19. Remove Nth Node From End of List, nthnode

19. Remove Nth Node From End of List, nthnode

 1 Given a linked list, remove the nth node from the end of list and return its head. 2  3 For example, 4  5    Given linked list: 1->2->3->4->5, and n = 2. 6  7    After removing the second node from the end, the linked list becomes 1->2->3->5. 8 Note: 9 Given n will always be valid.10 Try to do this in one pass.

 1 /** 2  * Definition for singly-linked list. 3  * struct ListNode { 4  *     int val; 5  *     struct ListNode *next; 6  * }; 7  */ 8 struct ListNode* removeNthFromEnd(struct ListNode* head, int n) { 9     struct ListNode* cur;10     struct ListNode* pre;11     cur = head;12     pre = head;13     if(head == NULL)14         return head;15     while(n)16     {17         cur = cur->next;18         n--;19     }20     if(cur == NULL){21         head = head->next;22         return head;23     }24     while(cur->next != NULL){25         cur = cur->next;26         pre = pre->next;27     }28     pre->next = pre->next->next;29     return head;30     31 }