Longest Increasing Subsequence — LeetCode 300 Python Solution

The problem

Given an integer array nums, return the length of the longest strictly increasing subsequence.

Example

Input

nums = [10,9,2,5,3,7,101,18]

Output

4

Explanation

The longest increasing subsequence is [2,3,7,101], therefore the length is 4.

Python solution

class Solution:
    def lengthOfLIS(self, nums: List[int]) -> int:
        n = len(nums)
        f = [1] * n
        for i in range(1, n):
            for j in range(i):
                if nums[j] < nums[i]:
                    f[i] = max(f[i], f[j] + 1)
        return max(f)

Complexity

Pattern: Monotonic Stack

Answer "what is the next greater element" for every position in one pass. LeetCode 300. Longest Increasing Subsequence is filed here because the reference solution below belongs to the algorithm family this hub collects, even though its LeetCode tags point elsewhere.

The monotonic stack guide has the Python template for the pattern and the 225 LeetCode problems that use it.

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