# 708. Insert into a Cyclic Sorted List

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`

``````class Solution {
public:
Node* insert(Node* head, int insertVal) {
}
Node *pre = head, *cur = pre->next;
if (pre->val <= insertVal && cur->val >= insertVal) break;
if (pre->val > cur->val && (pre->val <= insertVal || cur->val >= insertVal)) break;
pre = cur;
cur = cur->next;
}
pre->next = new Node(insertVal, cur);
}
};
``````

Insertion Sort List

https://leetcode.com/problems/insert-into-a-cyclic-sorted-list/

https://leetcode.com/problems/insert-into-a-cyclic-sorted-list/discuss/189351/java-one-pass-solution-and-easy-understand

https://leetcode.com/problems/insert-into-a-cyclic-sorted-list/discuss/136918/(Accepted)-C%2B%2B-Solution-in-O(n)-with-Explanation

LeetCode All in One 题目讲解汇总(持续更新中…)

 微信打赏 Venmo 打赏
（欢迎加入博主的知识星球，博主将及时答疑解惑，并分享刷题经验与总结，试运营期间前五十位可享受半价优惠～）

×

Help us with donation