Given an integer array nums, return the length of the longest strictly increasing subsequence.
A subsequence is a sequence derived from the array by deleting some or no elements without changing the order of the remaining elements.
Input: nums = [10, 9, 2, 5, 3, 7, 101, 18] Output: 4 Explanation: The longest increasing subsequence is [2, 3, 7, 101], with length 4.
Input: nums = [0, 1, 0, 3, 2, 3] Output: 4 Explanation: One valid subsequence is [0, 1, 2, 3].
Input: nums = [7, 7, 7, 7, 7] Output: 1 Explanation: Because the subsequence must be strictly increasing, equal elements cannot extend it.
nums = [10, 9, 2, 5, 3, 7, 101, 18]