如何将int值插入到链表中，保持排序？

class ListNode {
    int val;
    ListNode next;

    ListNode(int val) {
        this.val = val;
    }
}

public class InsertIntoSortedList {
    public ListNode insert(ListNode head, int val) {
        ListNode newNode = new ListNode(val);

        if (head == null) {
            return newNode;
        }

        if (val < head.val) {
            newNode.next = head;
            return newNode;
        }

        ListNode curr = head;
        while (curr.next != null && val >= curr.next.val) {
            curr = curr.next;
        }

        newNode.next = curr.next;
        curr.next = newNode;

        return head;
    }
}