### Question:
TwoSum { public int[] twoSum(int[] nums, int target) { int len = nums.length; HashMap<Integer, Integer> map = new HashMap<>(); for (int i = 0; i < len; ++i) { if (map.containsKey(nums[i])) { return new int[]{map.get(nums[i]), i}; } map.put(target - nums[i], i); } return null; }  int[] twoSum(int[] nums, int target); int[] twoSum1(int[] nums, int target);  }### Answer:
@Test void twoSum() { }