713.Subarray Product Less Than K

713.Subarray Product Less Than K

• 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.

• 题目大意：给定一个非负数组，计算子序列的乘积小于k。

• 思路：滑动窗口。
• 代码：

  package Array;      /**   * @Author OovEver   * @Date 2017/11/28 10:10   */  public class Solution {      public int numSubarrayProductLessThanK(int[] nums, int k) {          if (k < 2) {              return 0;          }          int result = 0;          int product = 1;          for(int i=0,right=0;right<nums.length;right++) {              product *= nums[right];              while (i <= right && product >= k) {                  product /= nums[i++];              }              result += right - i + 1;          }          return result;      }  }