import java.util.HashMap;

public class TwoSumArray {

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

HashMap<Integer, Integer> map = new HashMap<>();

for (int i = 0; i < nums.length; i++) {

int complement = target - nums[i];

if (map.containsKey(complement)) {

return new int[]{map.get(complement), i};

}

map.put(nums[i], i);

}

return new int[]{}; // no solution

}

public static void main(String[] args) {

TwoSumArray obj = new TwoSumArray();

int[] nums = {2, 7, 11, 15};

int target = 9;

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

System.out.print("Indices: ");

for (int i : result) {

System.out.print(i + " ");

}

}

}