【CODE】Subarray Product Less Than K

713. Subarray Product Less Than K

Medium

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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.

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.

Note:

• 0 < nums.length <= 50000.
• 0 < nums[i] < 1000.
• 0 <= k < 10^6.

class Solution {
public:
    int numSubarrayProductLessThanK(vector<int>& nums, int k) {
        if(k<=1) return 0;
        int res=0,prod=1,left=0;
        for(int i=0;i<nums.size();i++){
            prod*=nums[i];
            while(prod>=k) prod/=nums[left++];
            res+=i-left+1;
        }
        return res;
    }
};

• https://www.cnblogs.com/grandyang/p/7753959.html
• Runtime: 132 ms, faster than 70.82% of C++ online submissions for Subarray Product Less Than K.
• Memory Usage: 18.2 MB, less than 80.00% of C++ online submissions for Subarray Product Less Than K.
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