Leetcode 708. Insert into a Sorted Circular Linked List

Seawolf

Given a node from a Circular Linked List which is sorted in ascending order, write a function to insert a value insertVal 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 be necessarily the smallest value in the circular list.

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.

If the list is empty (i.e., given node is null), you should create a new single circular list and return the reference to that single node. Otherwise, you should return the original given node.



Example 1:



Input: head = [3,4,1], insertVal = 2
Output: [3,4,1,2]
Explanation: 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.



Example 2:

Input: head = [], insertVal = 1
Output: [1]
Explanation: The list is empty (given head is null). We create a new single circular list and return the reference to that single node.
Example 3:

Input: head = [1], insertVal = 0
Output: [1,0]


Constraints:

0 <= Number of Nodes <= 5 * 10^4
-10^6 <= Node.val <= 10^6
-10^6 <= insertVal <= 10^6

1. """
   
2. # Definition for a Node.
   
3. class Node:
   
4.     def __init__(self, val=None, next=None):
   
5.         self.val = val
   
6.         self.next = next
   
7. """
   
8. 
   
9. class Solution:
   
10.     def insert(self, head: 'Node', insertVal: int) -> 'Node':
    
11.         if head == None:
    
12.             node = Node(insertVal)
    
13.             node.next = node
    
14.             return node
    
15.         
    
16.         max_val = head
    
17.         
    
18.         curt = head
    
19.         
    
20.         while curt.next != head and curt.next.val >= max_val.val:
    
21.             max_val = curt.next
    
22.             curt = curt.next
    
23.         
    
24.         min_val = max_val.next
    
25.         curt = min_val
    
26.         # print(curt.next.val)
    
27.         if insertVal > max_val.val or insertVal < min_val.val:
    
28.             node = Node(insertVal, min_val)
    
29.             max_val.next = node
    
30.             return head
    
31.         
    
32.         else:
    
33.             while curt.next.val < insertVal:
    
34.                 curt = curt.next
    
35.             
    
36.             node = Node(insertVal, curt.next)
    
37.             curt.next = node
    
38.             return head

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