Python | Leetcode Python题解之第446题等差数列划分II-子序列

题目：

题解：

class Solution:def numberOfArithmeticSlices(self, nums: List[int]) -> int:ans = 0f = [defaultdict(int) for _ in nums]for i, x in enumerate(nums):for j in range(i):d = x - nums[j]cnt = f[j][d]ans += cntf[i][d] += cnt + 1return ans