function mergeKLists(lists: Array<ListNode | null>): ListNode | null {
    // If the list of lists is empty, return null
    if (lists.length === 0) {
        return null;
    }
    // If the list of lists has only one list, return that list
    if (lists.length === 1) {
        return lists[0];
    }
    // Find the middle index of the list of lists
    const mid = Math.floor(lists.length / 2);
    // Recursively merge the left half of the list of lists
    const left = mergeKLists(lists.slice(0, mid));
    // Recursively merge the right half of the list of lists
    const right = mergeKLists(lists.slice(mid));
    // Merge the two halves and return the result
    return mergeTwoLists(left, right);
}

// Helper function to merge two sorted lists
function mergeTwoLists(l1: ListNode | null, l2: ListNode | null): ListNode | null {
    // Create a dummy head node for the merged list
    const dummy = new ListNode();
    // Initialize the current node to the dummy node
    let curr = dummy;
    // While both lists are not null
    while (l1 && l2) {
        // If the value of l1 is smaller than or equal to the value of l2
        if (l1.val <= l2.val) {
            // Append l1 to the merged list
            curr.next = l1;
            // Move l1 to the next node
            l1 = l1.next;
        }
        // Otherwise
        else {
            // Append l2 to the merged list
            curr.next = l2;
            // Move l2 to the next node
            l2 = l2.next;
        }
        // Move the current node to the next node
        curr = curr.next;
    }
    // If l1 is not null, append the remaining nodes of l1 to the merged list
    if (l1) {
        curr.next = l1;
    }
    // If l2 is not null, append the remaining nodes of l2 to the merged list
    if (l2) {
        curr.next = l2;
    }
    // Return the head of the merged list
    return dummy.next;
}