code: def combination_sum_bottom_up(nums, target):
      """Find number of possible combinations in nums that add up to target, in bottom-up manner.
  
      Keyword arguments:
      nums -- positive integer array without duplicates
      target -- integer describing what a valid combination should add to
      """
      combs = [0] * (target + 1)
      combs[0] = 1
      for i in range(0, len(combs)):
          for num in nums:
              if i - num >= 0:
                  combs[i] += combs[i - num]
      return combs[target]
  
label_desc: Use image node_id 3 for calling a global function with example usage: combination_sum_bottom_up(nums, target) and returns: combs