. - 力扣（LeetCode）

class Solution {
public:int numSubarrayProductLessThanK(vector<int>& nums, int k) {if (k == 0) {return 0;}int n = nums.size();vector<double> logPrefix(n + 1);for (int i = 0; i < n; i++) {logPrefix[i + 1] = logPrefix[i] + log(nums[i]);}double logk = log(k);int ret = 0;for (int j = 0; j < n; j++) {int l = upper_bound(logPrefix.begin(), logPrefix.begin() + j + 1, logPrefix[j + 1] - log(k) + 1e-10) - logPrefix.begin();ret += j + 1 - l;}return ret;}
};