Compute length of longest increasing subsequence

You are given an integer array `nums` of length `n`. A **subsequence** of `nums` is a sequence that can be derived from `nums` by deleting zero or more elements without changing the order of the remaining elements. The elements of the subsequence do **not** need to be contiguous in the original array. A subsequence is called **strictly increasing** if every element is strictly greater than the previous one. **Task**: Return the length of the longest strictly increasing subsequence of `nums`. --- ### Example 1 Input: ```text nums = [10, 9, 2, 5, 3, 7, 101, 18] ``` One longest strictly increasing subsequence is `[2, 3, 7, 101]`, so the answer is `4`. Output: ```text 4 ``` ### Example 2 Input: ```text nums = [0, 1, 0, 3, 2, 3] ``` One longest strictly increasing subsequence is `[0, 1, 2, 3]`, so the answer is `4`. Output: ```text 4 ``` ### Example 3 Input: ```text nums = [7, 7, 7, 7] ``` Every strictly increasing subsequence has length `1` (any single element), so the answer is `1`. Output: ```text 1 ``` --- ### Constraints - `1 <= n <= 2 * 10^5` - `-10^9 <= nums[i] <= 10^9` Design an algorithm that can handle the largest constraint efficiently.