TreeSet : Ceiling in right side for every element in an array

              TreeSet is an example of Set Interface. Generally, it stores the elements in ascending order. It takes the elements with non-null value. It allows the multithreading.

Ceiling on the right-side Problem:

 It is a problem which checks the each element and the smallest element should be in right side.

Implementation:

Built in class: “TreeSet”

Functions:

•  finditCeilingOnRight(): This function is used to traverse the array from the right to left side.
•  Ceiling() : it checks the smallest with with current element.
• Add() :It inserts the element to the set.

Note :To update the ceiling value for result array ceil variable is used.

Steps to implement the program:

• Include the built in package java.util.*;
• Create a class “CeilingONRightsolution” with main() function.
• Get the input array elements.
• Call the function “finditCeilingOnRight()” with input array and assign it to output array.
• finditCeilingOnRight() – It finds the length of array. check the each and every element.
• Based on the comparison, it assign the smallest value in right or -1.
• Add the values to output set.
• Finally, the output is printed.

Program:

import java.util.*;

public class CeilingONRightsolution {

    public static void main(String[] args) {

        int[] arr1 = {12, 18, 40, 5, 35, 87,23};

        int[] output = finditCeilingOnRight(arr1);

        System.out.println("The input array is: " + Arrays.toString(arr1));

        System.out.println("The array after Ceiling on the right: " + Arrays.toString(output));

    }

     public static int[] finditCeilingOnRight(int[] arr1) {

        int len = arr1.length;

        int[] output = new int[len];

        TreeSet<Integer> set1 = new TreeSet<>();

        // iterating the array from right to left

        for (int i = len - 1; i >= 0; i--) {

            Integer ceil = set1.ceiling(arr1[i]);

            output[i] = (ceil != null) ? ceil : -1;

            set1.add(arr1[i]);

        }

                return output;

    }

}

Output:

C:\raji\blog>javac CeilingONRightsolution.java

C:\raji\blog>java CeilingONRightsolution

The input array is: [12, 18, 40, 5, 35, 87, 23]

The array after Ceiling on the right: [18, 23, 87, 23, 87, -1, -1]

This is the simple way of implementing this solution. Keep coding!!!