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Sort List

Problem statement​

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)?

My solution​

/**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} head
 * @return {ListNode}
 */
var sortList = function(head) {
    const arr = []
    let node = head;
    
    while (node) {
        arr.push(node.val)
        node = node.next;
    }
    
    arr.sort((a, b) => a - b);
    
    node = head;
    
    for (const n of arr) {
        node.val = n;
        node = node.next;
    }
    
    return head;
};