Given a linked list, remove the nth node from the end of list and return its head.
For example,
Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the linked list becomes 1->2->3->5.Note: Given n will always be valid.
Try to do this in one pass.
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* removeNthFromEnd(ListNode* head, int n) { ListNode* pre = new ListNode(1), *p2 = head; pre->next = head; while(n){ p2 = p2->next; n--; } if(!p2) return pre->next->next; while(p2){ p2 = p2->next; pre = pre->next; } pre->next = pre->next->next; return head; } };
