LeetCode 300 Longest Increasing Subsequence - Medium

300. Longest Increasing Subsequence — Medium

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Problem

Given an unsorted array of integers, find the length of longest increasing subsequence.

Example:

Input: [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. Note:

There may be more than one LIS combination, it is only necessary for you to return the length. Your algorithm should run in O(n2) complexity. Follow up: Could you improve it to O(n log n) time complexity?

Solution

class Solution:
    def lengthOfLIS(self, nums: List[int]) -> int:
        ### DP coords type problem:
        
        n = len(nums)
        
        f = [0] * n
        
        
        MAX = 0
        
        for i in range(n):
            f[i] = 1
            for j in range(i):
                if nums[j] < nums[i]:
                    f[i] = max(f[i], f[j]+1)
            MAX = max(f[i], MAX)
        
        return MAX