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Java Solution for LeetCode algorithm problems, continually updating
package g0301_0400.s0368_largest_divisible_subset;
// #Medium #Array #Dynamic_Programming #Math #Sorting
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Solution {
// Helper class containing value and an arraylist
private static class Helper {
int val;
List al;
Helper(int val) {
this.val = val;
al = new ArrayList<>();
}
}
public List largestDivisibleSubset(int[] nums) {
// Initializing Helper type array
Helper[] dp = new Helper[nums.length];
// Sorting given array
Arrays.sort(nums);
// max variable will keep track size of Longest Divisible Subset
int max = 0;
// index variable will keep track the index at which dp contains Longest Divisible Subset
int index = 0;
dp[0] = new Helper(1);
dp[0].al.add(nums[0]);
// Operation similar to LIS
for (int i = 1; i < nums.length; i++) {
int max2 = 0;
int pos = i;
for (int j = 0; j < i; j++) {
if (nums[i] % nums[j] == 0 && max2 < dp[j].val) {
max2 = dp[j].val;
pos = j;
}
}
// max2 = 0, means no element exists which can divide the present element
if (max2 == 0) {
dp[i] = new Helper(max2 + 1);
dp[i].al.add(nums[i]);
} else {
dp[i] = new Helper(max2 + 1);
for (int val : dp[pos].al) {
dp[i].al.add(val);
}
dp[i].al.add(nums[i]);
}
if (max2 > max) {
max = max2;
index = i;
}
}
// Returning Largest Divisible Subset
return dp[index].al;
}
}