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Java Array Exercises: Find all triplets equal to a given sum in a unsorted array of integers

Java Array: Exercise-74 with Solution

Write a Java program to find all triplets equal to a given sum in a unsorted array of integers.

Example:
Input :
nums = { 1, 6, 3, 0, 8, 4, 1, 7 }
Output:
Triplets of sum 7
(0 1 6)
(0 3 4)

Sample Solution:

Java Code:

import java.util.Arrays;

	class solution {
	
		public static void find_and_print_all_Triplets(int[] nums, int sum, int alen)
		{
		System.out.println("\nTriplets of sum "+sum);
		for (int i = 0; i <= alen - 3; i++)
			{
				int k = sum - nums[i];
				int l_index = i + 1, h_index = nums.length - 1;
	
				while (l_index < h_index)
				{
					if (nums[l_index] + nums[h_index] < k) {
						l_index++;
					}
	
				else if (nums[l_index] + nums[h_index] > k) {
						h_index--;
					}
	
					else {
						System.out.println("(" + nums[i] + " " + nums[l_index] + " " + nums[h_index] + ")");
						l_index++;
						h_index--;
					}
				}
			}
		}
		public static void main(String[] args)
		{
			int[] nums = { 1, 6, 3, 0, 8, 4, 1, 7 };
			int alen = nums.length;
			System.out.println("\nOriginal array: "+Arrays.toString(nums));
			// sort the array in ascending order
			Arrays.sort(nums);
			int sum = 7;
	
			find_and_print_all_Triplets(nums, sum, alen);
		}
	}

Sample Output:

Original array: [1, 6, 3, 0, 8, 4, 1, 7]

Triplets of sum 7
(0 1 6)
(0 3 4)

Flowchart:

Flowchart: Find all triplets equal to a given sum in a unsorted array of integers.

Java Code Editor:

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Previous: Write a Java program to sort a given array of distinct integers where all its numbers are sorted except two numbers.
Next: Java String Exercises

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Java: Tips of the Day

Array vs ArrayLists:

The main difference between these two is that an Array is of fixed size so once you have created an Array you cannot change it but the ArrayList is not of fixed size. You can create instances of ArrayLists without specifying its size. So if you create such instances of an ArrayList without specifying its size Java will create an instance of an ArrayList of default size.

Once an ArrayList is full it re-sizes itself. In fact, an ArrayList is internally supported by an array. So when an ArrayList is resized it will slow down its performance a bit as the contents of the old Array must be copied to a new Array.

At the same time, it's compulsory to specify the size of an Array directly or indirectly while creating it. And also Arrays can store both primitives and objects while ArrayLists only can store objects.

Ref: https://bit.ly/3o8L2KH