Welcome to the world of array problems in coding! As an engineer with intermediate knowledge of Java and Python, you are well-equipped to tackle array-related challenges.

Arrays are an essential data structure in programming, allowing you to store and manipulate collections of elements in a sequential manner. Array problems often test your ability to efficiently solve a specific task, such as finding a target sum, arranging elements in a certain order, or identifying patterns.

To illustrate this, let's consider a classic problem: finding two numbers in an array that add up to a target sum.

Here's a Java program that demonstrates the problem:

1class Main {
2    public static void main(String[] args) {
3        int[] nums = {1, 2, 3, 4, 5};
4        int target = 9;
5        int[] result = twoSum(nums, target);
6        System.out.println(Arrays.toString(result));
7    }
8
9    public static int[] twoSum(int[] nums, int target) {
10        int[] result = new int[2];
11        // Replace with your Java logic here
12        return result;
13    }
14}

In this program, we have an array nums containing the numbers {1, 2, 3, 4, 5}, and we want to find two numbers in the array that add up to the target sum of 9.

To solve this problem, we can use various approaches, such as using a two-pointer technique, employing a hash set to track elements, or utilizing nested loops to iterate over all possible pairs of numbers. The specific solution depends on the requirements and constraints of the problem.

Your task is to replace the comment Replace with your Java logic here with your own implementation of the twoSum method to solve the problem. Feel free to experiment with different approaches and optimize the solution for time and space complexity.

Once you have implemented the twoSum method, run the program and check if the correct pair of numbers is returned as the result.

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class Main {

    public static void main(String[] args) {

        int[] nums = {1, 2, 3, 4, 5};

        int target = 9;

        int[] result = twoSum(nums, target);

        System.out.println(Arrays.toString(result));

    }

​

    public static int[] twoSum(int[] nums, int target) {

        int[] result = new int[2];

        // Replace with your Java logic here

        return result;

    }

}