Longest Increasing Subsequence

Problem Find the length of the longest strictly increasing subsequence of an array. A subsequence keeps relative order but need not be contiguous.

Input / Output

• Input: an integer array nums.
• Output: the length of the longest strictly increasing subsequence.

Constraints

• 1 <= nums.length <= 2500
• Strictly increasing (equal values do not extend the sequence).

Example

• [10,9,2,5,3,7,101,18] -> 4 (e.g. [2,3,7,101]).