Largest Divisible Subset -- Leetcode

Question:

Given a set of distinct positive integers, find the largest subset such that every pair (Si, Sj) of elements in this subset satisfies: Si % Sj = 0 or Sj % Si = 0.

If there are multiple solutions, return any subset is fine.

Example 1:

nums: [1,2,3]

Result: [1,2] (of course, [1,3] will also be ok)

Example 2:

nums: [1,2,4,8]

Result: [1,2,4,8]

Answer:
Method: similar to Longest Increasing Subsequence. Using DP!
Time: O(n*n), Space:O(n)

public class Solution {
    public List<Integer> largestDivisibleSubset(int[] nums) {
        List<Integer> res = new ArrayList<Integer>();
        if(nums == null || nums.length==0){
            return res;
        }
     
        int length = nums.length;
        Arrays.sort(nums);
        //dp[i] record the previous element index satisfy longest divisible sequence ending with nums[i].
        int[] dp = new int[length];
        //len[i] record the longest divisible sequence ending with nums[i] length.
        int[] len = new int[length];
        int maxLen = 1;
        int maxLenFinalIndex = 0;
     
        for(int i=0;i<length;i++){
           dp[i] = i;
           len[i] = 1;

           for(int j=i-1;j>=0;j--){
               if(nums[i] % nums[j] == 0){
                   if(len[j] + 1 > len[i]){
                       len[i] = len[j] + 1;
                       dp[i] = j;
                   }
               }
           }
         
           if(len[i] > maxLen){
               maxLen = len[i];
               maxLenFinalIndex = i;
           }
        }
     
        int index = maxLenFinalIndex;
        int dpLen = maxLen;
        while(index >= 0 && dpLen > 0){
            res.add(nums[index]);
            index = dp[index];
            dpLen--;
        }
        Collections.reverse(res);
        return res;
    }
}