class Solution {
    public int[] twoSum(int[] nums, int target) {
        HashMap<Integer, Integer> stuff = new HashMap<>();
        for (int i=0; i<nums.length; i++){
            stuff.put(nums[i], i);
        }

        for (int i=0; i<nums.length; i++){
            if (stuff.containsKey(target-nums[i]) ){
                int otherIndex = stuff.get(target-nums[i]);
                if (i == otherIndex){
                    continue;
                }
                int returnVal[] = {i, otherIndex};
                return returnVal;
            }
        }
        return null;
    }
}