public class Solution {

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

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

            for (int j = i + 1; j < nums.length; j++) {

                if (nums[j] == (target - nums[i])) {
                    return new int[] {i, j};
                }

            }
        }

        return null;

    }

}

Create : 1 Two Sum
Create : 1 Two Sum
