给定一个链表,旋转链表,将链表每个节点向右移动 k 个位置,其中 k 是非负数。
这道题不难,就是不知道为什么运行时间比较慢。
python:
# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def rotateRight(self, head, k):
"""
:type head: ListNode
:type k: int
:rtype: ListNode
"""
if head == None:
return None
if head.next == None:
return head
test = ListNode(0)
test.next = head
length = 0
while test.next:
length += 1
test = test.next
for i in range(k % length):
original = head
while original.next.next:
original = original.next
temp = ListNode(original.next.val)
original.next = None
temp.next = head
head = temp
return head
C++:
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* rotateRight(ListNode* head, int k) {
if(head == NULL) return NULL;
if(head->next == NULL) return head;
int len = 0;
ListNode* temp = new ListNode(0);
temp->next = head;
while(temp->next){
temp = temp->next;
len += 1;
}
for(int i = 0;i < (k % len);i++){
ListNode* original = head;
while((original->next)->next){
original = original->next;
}
ListNode* start = new ListNode((original->next)->val);
original->next = NULL;
start->next = head;
head = start;
}
return head;
}
};