input: Write a function to find the highest product obtained by multiplying the elements of an increasing subsequence in an array.
  assert max_product([3, 100, 4, 5, 150, 6], 6) == 45000 
  assert max_product([4, 42, 55, 68, 80], 5) == 50265600
  assert max_product([10, 22, 9, 33, 21, 50, 41, 60], 8) == 21780000
output: def max_product(arr, n):
      dp = arr[:] 
      for i in range(1, n):
          for j in range(i):
              if arr[i] > arr[j] and dp[i] < dp[j] * arr[i]:
                  dp[i] = dp[j] * arr[i]
      return max(dp)