题目
Your are given an array of positive integers nums.
Count and print the number of (contiguous) subarrays where the product of all the elements in the subarray is less than k.
解题思路
使用双指针，枚举右端点r，如果连续的乘积小于k，那么以r为右端点的成绩小于k的子数组的个数为r-l+1个，否则就向右移动左端点
代码
class Solution:
def numSubarrayProductLessThanK(self, nums: List[int], k: int) -> int:
if k <= 1:
return 0
prod = 1
res = l = 0
for r, val in enumerate(nums):
prod *= val
while prod >= k:
prod /= nums[l]
l += 1
res += r - l + 1
return res
