솜씨좋은장씨

Given the head of a linked list, return the list after sorting it in ascending order. Follow up: Can you sort the linked list in O(n logn) time and O(1) memory (i.e. constant space)? 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,..