input: Write a function to find the maximum sum of an array of non-negative integers, given an upper limit value. If the given array is empty then return 0.
  assert findMaxSum(10, [1, 3, 5, 4, 2, 6])==10
  assert findMaxSum(15, [4, 6, 8, 3])==13
  assert findMaxSum(5, [2, 0, 1, 2, 3, 0])==5
  assert findMaxSum(20, [1, 3, 5, 4, 2, 6, 7, 8, 9])==18
  assert findMaxSum(0, [])==0
output: def findMaxSum(limit, arr):
      if not arr:
          return 0
      arr.sort(reverse=True)
      current_sum = 0
      for num in arr:
          if current_sum + num <= limit:
              current_sum += num
          if current_sum == limit:
              break
      return current_sum