Class BeautifulArray

Leetcode/Java/BeautifulArray.java:19–57

import java.io.*;

class BeautifulArray 
{
    public int[] beautifulArray(int n) 
    {
        ArrayList<Integer> arr = new ArrayList<>();
        arr.add(1);
        while(arr.size()<n)
        {
            ArrayList<Integer> tmp = new ArrayList<>();
            for(int i : arr)
            {
                if(2*i - 1 <=n)
                    tmp.add(2*i - 1);
            }
            for(int i : arr)
            {
                if(2*i <=n)
                    tmp.add(2*i);
            }
            arr = tmp;
        }
        int ans[]= new int[arr.size()];
        for(int i = 0; i<arr.size(); i++)
            ans[i] = arr.get(i);
        
        return ans;
    }
    
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        BeautifulArray obj = new BeautifulArray();
        int n = sc.nextInt();
        int ans[] = obj.beautifulArray(n);
        for(int i = 0; i<ans.length ; i++)
            System.out.print(ans[i]+" ");
            
    }
}

/*
 * Time Complexity: O(N*logN)