Arithmetic slices counter

1  def count_arithmetic_slices(nums: list[int]) -> int:
2      n = len(nums)
3      dp = [0] * n
4  
5      for i in range(2, n):
6          if nums[i] - nums[i-1] == nums[i-1] - nums[i-2]:
7              dp[i] = dp[i - 1] + 1
8  
9      return sum(dp)
10