61. Rotate List【M】【54】【leetcode】

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原创最新推荐文章于 2025-12-03 23:35:37 发布 · 410 阅读

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#leetcode #链表

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本文介绍了一种链表操作的方法——链表右旋。通过计算链表长度并利用基本的链表操作技巧，实现了将链表向右旋转k个位置的功能。

Given a list, rotate the list to the right by k places, where k is non-negative.

For example:
Given 1->2->3->4->5->NULL and k = 2,
return 4->5->1->2->3->NULL.

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先算出list的长度，然后再用最朴素的想法来完成

class Solution(object):
    def rotateRight(self, head, k):
        if k == 0 or head == None:
            return head
        if not head.next:
            return head
        h = head

        l = 0
        while h:
            l += 1
            tail = h
            h = h.next
        #print l
        k = k % l
        if k == 0:
            return head

        count = 0
        h = head
        new_h = ListNode(0)

        while count < l - k:
            prv = h
            h = h.next
            count += 1

        new_h.next = h
        tail.next = head
        prv.next = None
        return new_h.next