0300 - Longest Increasing Subsequence

0300 - Longest Increasing Subsequence

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

A subsequence is a sequence that can be derived from an array by deleting some or no elements without changing the order of the remaining elements. For example, [3,6,2,7] is a subsequence of the array [0,3,1,6,2,2,7].

Examples

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.

Input: nums = [0,1,0,3,2,3] Output: 4

Input: nums = [7,7,7,7,7,7,7] Output: 1

Constraints

• 1 <= nums.length <= 2500

• -104 <= nums[i] <= 104

Java Solution (Dynammic Programming)

class Solution {
    public int lengthOfLIS(int[] nums) {
        int[] dp = new int[nums.length];
        Arrays.fill(dp, 1);
        
        for(int i = 1; i < nums.length; i++) {
            for(int j = 0; j < i; j++) {
                if(nums[i] > nums[j]) dp[i] = Math.max(dp[i], dp[j]+1);
            }
        }
        
        int longest = 0;
        for(int num : dp) longest = Math.max(num, longest);
        
        return longest;
    }
}