Longest Increasing Subsequence

shriyanshi24jindal

Mar 28th, 2026

Never

Not a member of GistPad yet? Sign Up, it unlocks many cool features!

Java 9.34 KB | None | 0 0

copy raw download clone embed print report

class Solution {
// idea : create a new array say 'arr' which has sorted and unique elements from original array
// find LCS between two arrays
public int lengthOfLIS(int[] nums) {
int n = nums.length;
// store the original array into hashset to ignore the duplicates
Set<Integer> set = new HashSet<>();
for(int ele : nums)
set.add(ele);
// sort the elements in hashset by storing into array list
List<Integer> arr = new ArrayList<>();
arr.addAll(set);
Collections.sort(arr);
int m = arr.size();
// create a matrix
int[][] t = new int[n+1][m+1];
// intialise the matrix with base condition
for(int i=0; i<n+1; i++)
{
for(int j=0; j<m+1; j++)
{
if(i == 0 || j == 0)
t[i][j] = 0;
}
}
// same as LCS
for(int i=1; i<n+1; i++)
{
for(int j=1; j<m+1; j++)
{
if(nums[i-1] == arr.get(j-1))
{
t[i][j] = 1 + t[i-1][j-1];
}
else
t[i][j] = Math.max(t[i-1][j], t[i][j-1]);
}
}
return t[n][m];
}
}

RAW Paste Data Copied

class Solution {
    // idea : create a new array say 'arr' which has sorted and unique elements from original array
    // find LCS between two arrays
    
    public int lengthOfLIS(int[] nums) {
        int n = nums.length;

// store the original array into hashset to ignore the duplicates
        Set<Integer> set = new HashSet<>();
        for(int ele : nums)
            set.add(ele);

// sort the elements in hashset by storing into array list
        List<Integer> arr = new ArrayList<>();
        arr.addAll(set);
        Collections.sort(arr);

int m = arr.size();

// create a matrix
        int[][] t = new int[n+1][m+1];

// intialise the matrix with base condition
        for(int i=0; i<n+1; i++)
        {
            for(int j=0; j<m+1; j++)
            {
                if(i == 0 || j == 0)
                    t[i][j] = 0;
            }
        }

// same as LCS
        for(int i=1; i<n+1; i++)
        {
            for(int j=1; j<m+1; j++)
            {
                if(nums[i-1] == arr.get(j-1))
                {
                    t[i][j] = 1 + t[i-1][j-1];
                }
                else
                    t[i][j] = Math.max(t[i-1][j], t[i][j-1]);
            }
        }

return t[n][m];
    }
}