Given an array of integers, find two numbers such that they add up to a specific number. The solution twosum should return indices of the two numbers, where index1 must be less than index2. The returned number shouldn't be zero based. Assume that each input would have exactly one solution.

Two Sum

def twosum nums
  idx = 0 
  idx2 = idx + 1

  while idx < nums.length
  	n = nums[idx]
  	i = nums[idx2]
  	sum = n + i

  	if sum == 0
  		puts [idx, idx2]
      
    end
    
    idx += 1
  end
end

twosum [1,3,5,-3]