Leetcode Two Sum

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import java.util.Arrays;
import java.util.HashMap;

public class TwoSum {
    public static void main(String[] args) {
        int[] givenArray = new int[]{100, 400, 200};
        int givenTargetNumber = 300;


        int[] actual = twoSum(givenArray, givenTargetNumber);

        System.out.println(Arrays.toString(actual));
    }

    private static int[] twoSum(int[] array, int targetSum) {
        HashMap<Integer, Integer> map = new HashMap<>();

        for (int i = 0; i < array.length; i++) {
            int neededNumber = targetSum - array[i];

            if (map.containsKey(neededNumber)) {
                return new int[]{
                        map.get(neededNumber),
                        i
                };
            }
            map.put(array[i], i);
        }

        return new int[]{};

    }

}