aloalgoLinked List Strictly Increasing or Decreasing
Easy
You are given the head of a singly linked list, determine if the list is either strictly increasing or strictly decreasing.
- A linked list is strictly increasing if for every node, its value is greater than the value of the previous node.
- A linked list is strictly decreasing if for every node, its value is less than the value of the previous node.
An empty list or a list with a single node is considered to be both strictly increasing and strictly decreasing.
Example 1
Input
1 → 3 → 5 → 8 → null
Output
True
Explanation:
The list is strictly increasing: 1 < 3 < 5 < 8.
Example 2
Input
10 → 7 → 4 → 1 → null
Output
True
Explanation:
The list is strictly decreasing: 10 > 7 > 4 > 1.
Example 3
Input
1 → 3 → 3 → 5 → null
Output
False
Explanation:
The list is not strictly increasing because 3 is not greater than 3.
Example 4
Input
1 → 5 → 2 → null
Output
False
Explanation:
The list is neither strictly increasing nor strictly decreasing.
Input
1 → 3 → 5 → 8 → null
Output
True