713. 乘积小于 K 的子数组

for (int i = 0, j = 0; i < n; ++i) {
    while (j < i && check(j, i)) {
        ++j;
    }
    // 具体问题的逻辑
}

class Solution:
    def numSubarrayProductLessThanK(self, nums: List[int], k: int) -> int:
        ans, s, j = 0, 1, 0
        for i, v in enumerate(nums):
            s *= v
            while j <= i and s >= k:
                s //= nums[j]
                j += 1
            ans += i - j + 1
        return ans

class Solution {
    public int numSubarrayProductLessThanK(int[] nums, int k) {
        int ans = 0;
        for (int i = 0, j = 0, s = 1; i < nums.length; ++i) {
            s *= nums[i];
            while (j <= i && s >= k) {
                s /= nums[j++];
            }
            ans += i - j + 1;
        }
        return ans;
    }
}

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

func numSubarrayProductLessThanK(nums []int, k int) int {
	ans := 0
	for i, j, s := 0, 0, 1; i < len(nums); i++ {
		s *= nums[i]
		for ; j <= i && s >= k; j++ {
			s /= nums[j]
		}
		ans += i - j + 1
	}
	return ans
}

function numSubarrayProductLessThanK(nums: number[], k: number): number {
    let ans = 0;
    for (let i = 0, j = 0, s = 1; i < nums.length; ++i) {
        s *= nums[i];
        while (j <= i && s >= k) {
            s /= nums[j++];
        }
        ans += i - j + 1;
    }
    return ans;
}

impl Solution {
    pub fn num_subarray_product_less_than_k(nums: Vec<i32>, k: i32) -> i32 {
        if k <= 1 {
            return 0;
        }

        let mut res = 0;
        let mut product = 1;
        let mut i = 0;
        nums.iter().enumerate().for_each(|(j, v)| {
            product *= v;
            while product >= k {
                product /= nums[i];
                i += 1;
            }
            res += j - i + 1;
        });
        res as i32
    }
}