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) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
if(head==NULL)return NULL;
vector<ListNode*> record;
ListNode* ptr=head;
while(ptr!=NULL){
record.push_back(ptr);
ptr=ptr->next;
}
int total=record.size();
if(record.size()==n)return head->next;
else if(n==1){
record[total-2]->next=NULL;
}
else{
record[total-n-1]->next=record[total-n+1];
}
return head;
}
};