19. Remove Nth Node From End of List**
https://leetcode.com/problems/remove-nth-node-from-end-of-list/
题目描述
Given a linked list, remove the n-th node from the end of list and return its head.
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.
Follow up:
Could you do this in one pass?
C++ 实现 1
class Solution {
public:
ListNode* removeNthFromEnd(ListNode* head, int n) {
ListNode *dummy = new ListNode(0);
dummy->next = head;
auto q = dummy;
for (int i = 0; i <= n; ++ i) q = q->next;
auto prev = dummy;
while (q) {
prev = prev->next;
q = q->next;
}
prev->next = prev->next->next;
return dummy->next;
}
};
