using System;

public class Program

{

    public static void Main()

    {

        //Input1 should return [0, 1]

        var input1 = new int[] {2,7,11,15};

        var sum1 = 9;

        var result1 = SumOfPair(input1, sum1);

        Console.WriteLine("[{0}]", string.Join(", ", result1));

    }

    //Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.

    //You may assume that each input would have exactly one solution, and you may not use the same element twice.

    //You can return the answer in any order.

    public static int[] SumOfPair(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;

    }

}