🌵61. Rotate List
https://leetcode.com/problems/rotate-list/
js
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} head
* @param {number} k
* @return {ListNode}
*/
var rotateRight = function(head, k) {
if (!head || !k) {
return head
}
var current = head
var size = 1
while (current.next) {
current = current.next
size++
}
if (!(k = k % size)) {
return head
}
var fast = head
var slow = head
for (let i = 0; i < k; i++) {
fast = fast.next
}
while (fast.next) {
fast = fast.next
slow = slow.next
}
fast.next = head
head = slow.next
slow.next = null
return head
}py
# 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 not head or not k:
return head
current, size = head, 1
while current.next:
current = current.next
size += 1
k = k % size
if not k:
return head
fast = slow = head
for i in range(k):
fast = fast.next
while fast.next:
fast = fast.next
slow = slow.next
fast.next = head
head = slow.next
slow.next = None
return head