LeetCode-in-All
148. Sort List
Medium
Given the head of a linked list, return the list after sorting it in ascending order.
Example 1:
Input: head = [4,2,1,3]
Output: [1,2,3,4]
Example 2:
Input: head = [-1,5,3,4,0]
Output: [-1,0,3,4,5]
Example 3:
Input: head = []
Output: []
Constraints:
- The number of nodes in the list is in the range
[0, 5 * 104]. -105 <= Node.val <= 105
Follow up: Can you sort the linked list in O(n logn) time and O(1) memory (i.e. constant space)?
Solution
require_relative '../../com_github_leetcode/list_node'
# Definition for singly-linked list.
# class ListNode
# attr_accessor :val, :next
# def initialize(val = 0, _next = nil)
# @val = val
# @next = _next
# end
# end
# @param {ListNode} head
# @return {ListNode}
def sort_list(head)
list = []
new_head = ListNode.new
while head
list << head.val
head = head.next
end
curr = new_head
list.sort.each do |v|
curr.next = ListNode.new(v)
curr = curr.next
end
new_head.next
end