给定一个链表,移除从尾部起的第 n 个结点,并且返回它的头结点。
例如,给定链表:1->2->3->4->5,n = 2。
在移除尾部起第二个结点后,链表将变成:1->2->3->5。
备注:
给定的 n 是有效的,代码尽量一次通过。
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.
class Solution{ public: ListNode* removeNthFromEnd(ListNode* head, int n){ ListNode newHead(0); newHead.next = head; count = n; return solution1(&newHead); } private: int count; ListNode* solution1(ListNode* newHead){ subSol1(newHead); return newHead->next; } bool subSol1(ListNode* node){ if(!node) return false; if(subSol1(node->next)) return true; if(count--) return false; ListNode *tmp = node->next; node->next = tmp->next; delete tmp; return true; } };