最长递增子序列的个数

class Solution:    def findNumberOfLIS(self, nums):        n = len(nums)        length = [1] * n        count = [1] * n        for i in range(n):            for j in range(i):                if nums[j] < nums[i]:                    if length[j] + 1 > length[i]:                        length[i] = length[j] + 1                        count[i] = count[j]                    elif length[j] + 1 == length[i]:                        count[i] += count[j]        longest = max(length)        return sum(c for l, c in zip(length, count) if l == longest)