Today I have done leetcode's March LeetCoding Challenge with cpp.

March LeetCoding Challenge 27

Description

Subarray Product Less Than K

Given an array of integers nums and an integer k, return the number of contiguous subarrays where the product of all the elements in the subarray is strictly less than k.

Example 1:

Input: nums = [10,5,2,6], k = 100
Output: 8
Explanation: The 8 subarrays that have product less than 100 are:
[10], [5], [2], [6], [10, 5], [5, 2], [2, 6], [5, 2, 6]
Note that [10, 5, 2] is not included as the product of 100 is not strictly less than k.

Example 2:

Input: nums = [1,2,3], k = 0
Output: 0

Constraints:

• 1 <= nums.length <= 3 * 104
• 1 <= nums[i] <= 1000
• 0 <= k <= 106

Solution

class Solution {
public:
  int numSubarrayProductLessThanK(vector<int>& nums, int k) {
    if(k <= 1) return 0;
    int begin = 0; 
    int product = 1;
    int answer = 0;
    int len = nums.size();
    for(int end = 0; end < len; ++end) {
      product *= nums[end];
      while(product >= k) product /= nums[begin++];
      answer += end - begin + 1;
    }
    return answer;
  }
};