a submitted solution to TwoSums problem in Leetcode

twoSums.java

// problem: https://leetcode.com/problems/two-sum/

import java.util.HashMap;
class Solution {
   
    int[] twoSum(int[] nums, int target){
        int firstIndex = -1, secondIndex = -1;

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

        for (int i = 0; i < nums.length;i++){
            map.put(target - nums[i], i);
        }

        for (int i = 0; i < nums.length;i++){
            if (!map.containsKey(nums[i])) continue;
            int cur = map.get(nums[i]);
            if (nums[cur] + nums[i] == target && cur != i){
                firstIndex = i;
                secondIndex = cur;
                break;
            }
        }
        // can be removed at submission
        if (firstIndex == -1){
            return null;
        }

        return new int[]{firstIndex, secondIndex};
    }

}