Insert into a Sorted Circular Linked List
<p>Given a Circular Linked List node, which is sorted in non-descending order, write a function to insert a value <code>insertVal</code> into the list such that it remains a sorted circular list. The given node can be a reference to any single node in the list and may not necessarily be the smallest value in the circular list.</p>

<p>If there are multiple suitable places for insertion, you may choose any place to insert the new value. After the insertion, the circular list should remain sorted.</p>

<p>If the list is empty (i.e., the given node is <code>null</code>), you should create a new single circular list and return the reference to that single node. Otherwise, you should return the originally given node.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0700-0799/0708.Insert%20into%20a%20Sorted%20Circular%20Linked%20List/images/example_1_before_65p.jpg" style="width: 250px; height: 149px;" /><br />
&nbsp;
<pre>
<strong>Input:</strong> head = [3,4,1], insertVal = 2
<strong>Output:</strong> [3,4,1,2]
<strong>Explanation:</strong> In the figure above, there is a sorted circular list of three elements. You are given a reference to the node with value 3, and we need to insert 2 into the list. The new node should be inserted between node 1 and node 3. After the insertion, the list should look like this, and we should still return node 3.

<img alt="" src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0700-0799/0708.Insert%20into%20a%20Sorted%20Circular%20Linked%20List/images/example_1_after_65p.jpg" style="width: 250px; height: 149px;" />

</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> head = [], insertVal = 1
<strong>Output:</strong> [1]
<strong>Explanation:</strong> The list is empty (given head is&nbsp;<code>null</code>). We create a new single circular list and return the reference to that single node.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> head = [1], insertVal = 0
<strong>Output:</strong> [1,0]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the list is in the range <code>[0, 5 * 10<sup>4</sup>]</code>.</li>
	<li><code>-10<sup>6</sup> &lt;= Node.val, insertVal &lt;= 10<sup>6</sup></code></li>
</ul>
Linked List
"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, next=None):
        self.val = val
        self.next = next
"""


class Solution:
    def insert(self, head: 'Optional[Node]', insertVal: int) -> 'Node':
        node = Node(insertVal)
        if head is None:
            node.next = node
            return node
        prev, curr = head, head.next
        while curr != head:
            if prev.val <= insertVal <= curr.val or (
                prev.val > curr.val and (insertVal >= prev.val or insertVal <= curr.val)
            ):
                break
            prev, curr = curr, curr.next
        prev.next = node
        node.next = curr
        return head
