Java Program to Find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number

In the previous article, we have seen Java Program to Check if an Array of Integers without 0 and 1

In this article we will see find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number.

Java Program to Find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number

Array is a data structure which stores a fixed size sequential collection of values of single type. Where with every array elements/values memory location is associated. Each array elements have it’s own index where array index starts from 0.

In Array set of variables referenced by a single variable name and it’s array index position. It is also called as a container object which contains elements of similar type.

Declaration of an array:

dataType[] arrayName; (or)                              //Declaring an array
dataType []arrayName; (or)
dataType arr[];

Instantiation of an Array:

arrayName = new datatype[size];                    //Allocating memory to array

Combining both Statements in One:

dataType[] arrayName = new dataType[size] //Declaring and Instantiating array

Initialization of an Array:

arrayName[index-0]= arrayElement1             //Initializing the array

...

arrayName[index-s]= arrayElementS

Combining all Statements in One:

dataType arrayName[ ]={e1,e2,e3};               //declaration, instantiation and initialization

Let’s see different ways to find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number

By Static Initialization of Array Elements
By Dynamic Initialization of Array Elements

Method-1: Java Program to Find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number By Static Initialization of Array Elements

Approach:

Declare and initialize an array.
Create three nested for loops.
First loop runs from start to end (counter i), second loop runs from i+1 to end (counter j) and third loop runs from j+1 to end (loop counter k)
Find the sum of ith, jth and kth element. If the sum is equal to given sum. Print the triplet and break.
If there is no triplet, then print that no triplet exists.

Program:

public class Main 
{
    public static void main(String[] args) 
    {
        int[] arr = { 2, 5, 7, 9, 3, -2, 1 };
        int sum = 14;
        System.out.println("Finding triplets whose sum are equal to : "+sum);
        System.out.println("The triplets are : ");
        findTriplet(arr, sum);
}
    
public static void findTriplet(int[] arr, int sum) 
{
   int count = 1;
        for (int i = 0; i < arr.length; i++) 
        {
            for (int j = i + 1; j < arr.length; j++) 
            {
                for (int k = j + 1; k < arr.length; k++) 
                {
                    if (arr[i] + arr[j] + arr[k] == sum) 
                    {
                        System.out.println("Triplet " + count + ": " + arr[i] + " " + arr[j] + " " + arr[k]);
                        count++;
                        break;
                    }
                }
            }
        }
    }
}

Output:

Finding triplets whose sum are equal to : 14
The triplets are : 
Triplet 1: 2 5 7
Triplet 2: 2 9 3
Triplet 3: 7 9 -2

Method-2: Java Program to Find all the Triplets Where Sum of All the Three Elements are Equal to a Specified Number By Dynamic Initialization of Array Elements

Approach:

Ask use length of the array.
Initialize the array with given size.
Ask the user for array elements.
Create three nested for loops.
First loop runs from start to end (counter i), second loop runs from i+1 to end (counter j) and third loop runs from j+1 to end (loop counter k)
Find the sum of ith, jth and kth element. If the sum is equal to given sum. Print the triplet and break.
If there is no triplet, then print that no triplet exists.

Program:

import java.util.*;

public class Main 
{
    public static void main(String[] args) 
    {
         Scanner sc = new Scanner(System.in);
        // asking user to enter the number of elements
        System.out.println("Enter number of elements in the array: ");
        int n = sc.nextInt();
        // initializing the array
        int[] arr = new int[n];
        // asking user to enter the elements
        System.out.println("Enter elements of the array: ");
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        // asking user to enter the sum
        System.out.println("Enter sum: ");
        int sum = sc.nextInt();

        System.out.println("Finding triplets whose sum are equal to : "+sum);
        System.out.println("The triplets are : ");
        findTriplet(arr, sum);
}
    
public static void findTriplet(int[] arr, int sum) 
{
   int count = 1;
        for (int i = 0; i < arr.length; i++) 
        {
            for (int j = i + 1; j < arr.length; j++) 
            {
                for (int k = j + 1; k < arr.length; k++) 
                {
                    if (arr[i] + arr[j] + arr[k] == sum) 
                    {
                        System.out.println("Triplet " + count + ": " + arr[i] + " " + arr[j] + " " + arr[k]);
                        count++;
                        break;
                    }
                }
            }
        }
    }
}

Output:

Enter number of elements in the array: 5
Enter elements of the array: 2 2 1 4 5
Enter sum: 5
Finding triplets whose sum are equal to : 5
The triplets are : 
Triplet 1: 2 2 1

Have you mastered basic programming topics of java and looking forward to mastering advanced topics in a java programming language? Go with these ultimate Advanced java programs examples with output & achieve your goal in improving java coding skills.

Related Java Programs: