61. Rotate List

Given the head of a linked list, rotate the list to the right by k places.

Example 1:

Input: head = [1,2,3,4,5], k = 2
Output: [4,5,1,2,3]

Example 2:

Input: head = [0,1,2], k = 4
Output: [2,0,1]

Constraints:

• The number of nodes in the list is in the range [0, 500].
• -100 <= Node.val <= 100
• 0 <= k <= 2 * 109

# @lc code=start
using LeetCode

function rotate_right(head::ListNode, k::Int)::ListNode
    isnothing(head) && return head

    last_element, length = head, 1
    while !isnothing(next(last_element))
        last_element = next(last_element)
        length += 1
    end

    k = k % length
    next!(last_element, head)

    temp_element = head
    for _ = 0:(length-k-2)
        temp_element = next(temp_element)
    end

    answer = next(temp_element)
    next!(temp_element, nothing)

    return answer
end
# @lc code=end

rotate_right (generic function with 1 method)

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