本文共 12205 字，大约阅读时间需要 40 分钟。
给定一个正整数数组 nums。
找出该数组内乘积小于 k 的连续的子数组的个数。
示例 1:
输入: nums = [10,5,2,6], k = 100输出: 8解释: 8个乘积小于100的子数组分别为: [10], [5], [2], [6], [10,5], [5,2], [2,6], [5,2,6]。需要注意的是 [10,5,2] 并不是乘积小于100的子数组。
说明:
0 < nums.length <= 500000 < nums[i] < 10000 <= k < 10^6package Solution713;import java.math.BigDecimal;import java.util.*;class Solution { public int numSubarrayProductLessThanK(int[] nums, int k) { int count = 0; // Pick starting point for (int i = 0; i < nums.length; i++) { // Pick ending point for (int j = i; j < nums.length; j++) { // Print subarray between current starting and ending points BigDecimal p = new BigDecimal(1);// int and long overflow for (int h = i; h <= j; h++) { BigDecimal n = new BigDecimal(nums[h]); p = p.multiply(n); ; } if (p.compareTo(new BigDecimal(k)) == -1) { count++; } } } return count; } public static void main(String args[]) { Solution sol = new Solution(); int[] nums = { 4, 32, 23, 1, 11, 21, 8, 3, 12, 21, 33, 5, 14, 11, 9, 14, 4, 27, 5, 7, 7, 14, 13, 9, 17, 10, 3, 4, 17, 31, 7, 19, 4, 7, 20, 5, 4, 3, 24, 30, 9, 11, 23, 16, 7, 21, 23, 22, 12, 20, 8, 20, 18, 11, 5, 8, 21, 5, 11, 31, 28, 21, 13, 21, 22, 3, 2, 1, 32, 8, 8, 27, 4, 26, 13, 14, 4, 15, 6, 10, 28, 15, 18, 20, 29, 1, 1, 12, 5, 18, 10, 9, 5, 13, 1, 2, 7, 3, 23, 26, 3, 4, 13, 9, 32, 32, 31, 26, 19, 8, 7, 29, 16, 21, 28, 14, 18, 5, 25, 3, 4, 33, 27, 3, 10, 10, 22, 13, 13, 32, 18, 11, 27, 12, 3, 33, 21, 3, 5, 23, 12, 23, 23, 20, 24, 31, 26, 7, 25, 1, 5, 28, 1, 1, 29, 7, 31, 20, 21, 32, 23, 24, 13, 21, 14, 30, 8, 5, 23, 26, 31, 31, 25, 33, 17, 30, 20, 20, 16, 16, 2, 8, 10, 5, 10, 16, 27, 8, 25, 5, 3, 22, 21, 30, 25, 20, 4, 10, 9, 4, 3, 20, 14, 13, 4, 3, 3, 1, 32, 29, 13, 25, 13, 28, 10, 26, 17, 29, 13, 28, 20, 22, 6, 6, 2, 30, 15, 2, 29, 21, 10, 28, 33, 22, 6, 25, 8, 18, 29, 17, 1, 25, 17, 27, 27, 28, 16, 18, 3, 4, 5, 28, 20, 32, 11, 23, 1, 33, 12, 7, 29, 32, 6, 33, 15, 33, 24, 13, 32, 15, 24, 20, 11, 27, 20, 7, 2, 21, 6, 11, 16, 27, 24, 22, 7, 4, 15, 16, 1, 25, 22, 16, 4, 9, 19, 16, 10, 14, 9, 30, 18, 17, 6, 8, 9, 23, 1, 9, 22, 20, 5, 1, 15, 30, 23, 3, 8, 10, 9, 22, 24, 9, 24, 9, 5, 20, 27, 16, 22, 7, 6, 11, 22, 27, 31, 16, 30, 8, 14, 12, 9, 2, 29, 33, 13, 18, 14, 30, 20, 19, 16, 33, 8, 31, 31, 30, 6, 15, 6, 2, 30, 15, 32, 17, 33, 14, 22, 2, 4, 23, 22, 21, 29, 8, 31, 26, 28, 26, 20, 12, 12, 18, 1, 20, 17, 8, 10, 10, 4, 5, 7, 28, 8, 31, 13, 11, 31, 17, 27, 27, 25, 10, 8, 30, 12, 17, 24, 19, 16, 31, 28, 15, 28, 17, 16, 7, 16, 1, 23, 7, 25, 11, 5, 19, 3, 1, 14, 10, 29, 19, 17, 29, 20, 20, 24, 5, 1, 29, 29, 14, 16, 2, 7, 29, 15, 14, 18, 14, 20, 4, 9, 30, 8, 28, 30, 18, 18, 15, 20, 6, 5, 2, 29, 3, 1, 29, 3, 6, 12, 16, 20, 27, 6, 5, 30, 14, 3, 9, 16, 15, 28, 2, 11, 22, 16, 12, 9, 15, 10, 22, 18, 13, 29, 31, 26, 31, 33, 21, 13, 20, 20, 12, 33, 15, 22, 7, 31, 24, 21, 21, 30, 7, 25, 31, 28, 25, 19, 8, 27, 27, 16, 31, 17, 12, 20, 30, 23, 15, 21, 1, 6, 10, 28, 10, 27, 31, 24, 9, 3, 23, 8, 30, 31, 2, 19, 8, 31, 3, 16, 30, 32, 1, 9, 9, 10, 30, 29, 12, 28, 20, 32, 22, 33, 2, 1, 18, 33, 32, 16, 9, 5, 21, 27, 29, 14, 6, 6, 21, 13, 23, 18, 15, 29, 21, 32, 29, 4, 9, 5, 33, 22, 7, 11, 17, 24, 10, 13, 4, 10, 1, 3, 11, 8, 12, 20, 18, 11, 8, 2, 25, 6, 25, 18, 1, 1, 21, 19, 11, 5, 2, 12, 7, 20, 20, 2, 31, 14, 26, 16, 15, 22, 6, 27, 6, 10, 20, 20, 31, 20, 13, 20, 12, 24, 15, 16, 23, 18, 3, 22, 22, 8, 20, 3, 5, 20, 16, 11, 11, 28, 2, 2, 32, 18, 28, 12, 32, 12, 27, 26, 30, 29, 4, 1, 22, 14, 7, 12, 23, 31, 11, 18, 7, 25, 12, 8, 24, 9, 14, 17, 25, 16, 4, 3, 29, 22, 17, 25, 17, 26, 22, 22, 19, 28, 2, 17, 24, 19, 18, 26, 9, 4, 25, 23, 15, 25, 23, 24, 29, 20, 18, 13, 22, 11, 9, 24, 12, 14, 6, 1, 22, 1, 21, 21, 8, 13, 15, 8, 29, 13, 2, 8, 17, 8, 27, 14, 6, 9, 29, 25, 31, 3, 10, 22, 30, 11, 19, 4, 12, 10, 6, 21, 27, 16, 22, 8, 32, 13, 6, 19, 30, 29, 26, 22, 2, 11, 8, 28, 17, 19, 10, 11, 19, 33, 23, 15, 12, 32, 31, 20, 5, 16, 11, 16, 4, 13, 24, 26, 18, 33, 14, 30, 33, 24, 19, 33, 19, 12, 27, 24, 29, 33, 13, 14, 10, 22, 25, 24, 32, 18, 5, 9, 6, 33, 27, 31, 26, 12, 16, 7, 30, 3, 12, 25, 11, 12, 28, 31, 5, 32, 13, 1, 5, 3, 26, 11, 25, 9, 28, 16, 3, 27, 13, 19, 18, 16, 12, 15, 18, 9, 4, 25, 6, 16, 14, 2, 10, 20, 22, 20, 20, 8, 7, 7, 5, 32, 30, 9, 27, 33, 22, 4, 13, 8, 6, 11, 18, 18, 27, 26, 27, 25, 15, 22, 16, 11, 13, 15, 25, 11, 29, 7, 3, 15, 26, 21, 27, 22, 29, 11, 16, 2, 25, 32, 24, 17, 11, 13, 15, 9, 33, 31, 14, 20, 22, 32, 4, 25, 13, 28, 33, 4, 9, 16, 20, 22, 6, 23, 7, 18, 30, 9, 12, 19, 32, 27, 33, 5, 22, 18, 9, 9, 6, 5, 5, 4, 4, 33, 16, 13, 5, 28, 24, 24, 6, 1, 14, 13, 12, 15, 10, 24, 22, 12, 10, 31, 33, 29, 24, 18, 18, 13, 25, 26, 32, 15, 3, 14, 14, 26, 19, 32, 15, 33, 33, 2, 6, 10, 24, 21, 21, 31, 31, 12, 22, 12, 6, 30, 32, 8, 16, 24, 26, 13, 13, 16, 5, 17, 26, 4, 4, 7, 27, 27, 5, 14, 24, 23, 32, 13, 3, 23, 10, 30, 23, 31, 30, 18, 25, 11, 24, 21, 7, 19, 13, 19, 4, 28, 22, 27, 2, 17, 12, 33, 32, 4, 25, 21, 23, 24, 7, 13, 21, 33, 7, 33, 31, 7, 20, 30, 13, 22, 19, 33, 16, 2, 20, 4, 31, 2, 31, 21, 12, 24, 23, 22, 2, 20, 19, 15, 2, 28, 4, 9, 30, 15, 13, 30, 4, 17, 24, 13, 32, 2, 12, 24, 24, 19, 11, 19, 6, 33, 2, 9, 26, 25, 16, 15, 24, 6, 15, 4, 28, 2, 3, 32, 18, 10, 2, 13, 24, 16, 13, 28, 28, 22, 33, 25, 21, 2, 5, 2, 21, 1, 8, 17, 2, 5, 18, 33, 29, 27, 20, 30, 27, 23, 25, 1, 8, 19, 33, 22, 30, 17, 24, 17, 7, 16, 16, 4, 25, 23, 4, 31, 12, 10, 30, 17, 17, 14, 4, 24, 10, 32, 13, 14, 15, 29, 17, 13, 7, 4, 21, 16, 23, 16, 2, 13, 12, 33, 23, 27, 33, 28, 15, 31, 25, 13, 12, 20, 14, 18, 18, 7, 31, 3, 31, 30, 33, 13, 6, 26, 13, 14, 33, 26, 4, 17, 13, 7, 15, 5, 18, 19, 24, 25, 15, 14, 33, 19, 26, 19, 16, 27, 20, 12, 6, 11, 6, 5, 17, 29, 17, 10, 25, 26, 10, 6, 8, 25, 5, 11, 11, 7, 32, 14, 2, 2, 32, 25, 12, 30, 20, 32, 18, 30, 19, 20, 30, 31, 11, 21, 13, 27, 22, 15, 9, 26, 4, 10, 4, 9, 2, 5, 5, 31, 14, 26, 32, 8, 30, 19, 16, 27, 6, 4, 12, 17, 18, 24, 13, 17, 16, 4, 5, 30, 11, 21, 21, 21, 4, 25, 26, 13, 2, 13, 2, 8, 32, 6, 12, 32, 9, 30, 15, 24, 11, 7, 26, 14, 10, 10, 22, 13, 28, 2, 21, 20, 19, 16, 1, 14, 16, 1, 26, 8, 3, 14, 4, 20, 1, 3, 21, 26, 25, 20, 1, 18, 17, 6, 16, 8, 17, 30, 24, 32, 9, 4, 24, 8, 23, 12, 28, 4, 32, 5 }; int k = 9931; System.out.println(sol.numSubarrayProductLessThanK(nums, k)); }} 超时
官方答案
package Solution713;import java.math.BigDecimal;import java.util.*;class Solution { public int numSubarrayProductLessThanK(int[] nums, int k) { if (k <= 1) return 0; int prod = 1, ans = 0, left = 0; for (int right = 0; right < nums.length; right++) { prod *= nums[right]; while (prod >= k) prod /= nums[left++]; ans += right - left + 1; } return ans; } public static void main(String args[]) { Solution sol = new Solution(); int[] nums = { 4, 32, 23, 1, 11, 21, 8, 3, 12, 21, 33, 5, 14, 11, 9, 14, 4, 27, 5, 7, 7, 14, 13, 9, 17, 10, 3, 4, 17, 31, 7, 19, 4, 7, 20, 5, 4, 3, 24, 30, 9, 11, 23, 16, 7, 21, 23, 22, 12, 20, 8, 20, 18, 11, 5, 8, 21, 5, 11, 31, 28, 21, 13, 21, 22, 3, 2, 1, 32, 8, 8, 27, 4, 26, 13, 14, 4, 15, 6, 10, 28, 15, 18, 20, 29, 1, 1, 12, 5, 18, 10, 9, 5, 13, 1, 2, 7, 3, 23, 26, 3, 4, 13, 9, 32, 32, 31, 26, 19, 8, 7, 29, 16, 21, 28, 14, 18, 5, 25, 3, 4, 33, 27, 3, 10, 10, 22, 13, 13, 32, 18, 11, 27, 12, 3, 33, 21, 3, 5, 23, 12, 23, 23, 20, 24, 31, 26, 7, 25, 1, 5, 28, 1, 1, 29, 7, 31, 20, 21, 32, 23, 24, 13, 21, 14, 30, 8, 5, 23, 26, 31, 31, 25, 33, 17, 30, 20, 20, 16, 16, 2, 8, 10, 5, 10, 16, 27, 8, 25, 5, 3, 22, 21, 30, 25, 20, 4, 10, 9, 4, 3, 20, 14, 13, 4, 3, 3, 1, 32, 29, 13, 25, 13, 28, 10, 26, 17, 29, 13, 28, 20, 22, 6, 6, 2, 30, 15, 2, 29, 21, 10, 28, 33, 22, 6, 25, 8, 18, 29, 17, 1, 25, 17, 27, 27, 28, 16, 18, 3, 4, 5, 28, 20, 32, 11, 23, 1, 33, 12, 7, 29, 32, 6, 33, 15, 33, 24, 13, 32, 15, 24, 20, 11, 27, 20, 7, 2, 21, 6, 11, 16, 27, 24, 22, 7, 4, 15, 16, 1, 25, 22, 16, 4, 9, 19, 16, 10, 14, 9, 30, 18, 17, 6, 8, 9, 23, 1, 9, 22, 20, 5, 1, 15, 30, 23, 3, 8, 10, 9, 22, 24, 9, 24, 9, 5, 20, 27, 16, 22, 7, 6, 11, 22, 27, 31, 16, 30, 8, 14, 12, 9, 2, 29, 33, 13, 18, 14, 30, 20, 19, 16, 33, 8, 31, 31, 30, 6, 15, 6, 2, 30, 15, 32, 17, 33, 14, 22, 2, 4, 23, 22, 21, 29, 8, 31, 26, 28, 26, 20, 12, 12, 18, 1, 20, 17, 8, 10, 10, 4, 5, 7, 28, 8, 31, 13, 11, 31, 17, 27, 27, 25, 10, 8, 30, 12, 17, 24, 19, 16, 31, 28, 15, 28, 17, 16, 7, 16, 1, 23, 7, 25, 11, 5, 19, 3, 1, 14, 10, 29, 19, 17, 29, 20, 20, 24, 5, 1, 29, 29, 14, 16, 2, 7, 29, 15, 14, 18, 14, 20, 4, 9, 30, 8, 28, 30, 18, 18, 15, 20, 6, 5, 2, 29, 3, 1, 29, 3, 6, 12, 16, 20, 27, 6, 5, 30, 14, 3, 9, 16, 15, 28, 2, 11, 22, 16, 12, 9, 15, 10, 22, 18, 13, 29, 31, 26, 31, 33, 21, 13, 20, 20, 12, 33, 15, 22, 7, 31, 24, 21, 21, 30, 7, 25, 31, 28, 25, 19, 8, 27, 27, 16, 31, 17, 12, 20, 30, 23, 15, 21, 1, 6, 10, 28, 10, 27, 31, 24, 9, 3, 23, 8, 30, 31, 2, 19, 8, 31, 3, 16, 30, 32, 1, 9, 9, 10, 30, 29, 12, 28, 20, 32, 22, 33, 2, 1, 18, 33, 32, 16, 9, 5, 21, 27, 29, 14, 6, 6, 21, 13, 23, 18, 15, 29, 21, 32, 29, 4, 9, 5, 33, 22, 7, 11, 17, 24, 10, 13, 4, 10, 1, 3, 11, 8, 12, 20, 18, 11, 8, 2, 25, 6, 25, 18, 1, 1, 21, 19, 11, 5, 2, 12, 7, 20, 20, 2, 31, 14, 26, 16, 15, 22, 6, 27, 6, 10, 20, 20, 31, 20, 13, 20, 12, 24, 15, 16, 23, 18, 3, 22, 22, 8, 20, 3, 5, 20, 16, 11, 11, 28, 2, 2, 32, 18, 28, 12, 32, 12, 27, 26, 30, 29, 4, 1, 22, 14, 7, 12, 23, 31, 11, 18, 7, 25, 12, 8, 24, 9, 14, 17, 25, 16, 4, 3, 29, 22, 17, 25, 17, 26, 22, 22, 19, 28, 2, 17, 24, 19, 18, 26, 9, 4, 25, 23, 15, 25, 23, 24, 29, 20, 18, 13, 22, 11, 9, 24, 12, 14, 6, 1, 22, 1, 21, 21, 8, 13, 15, 8, 29, 13, 2, 8, 17, 8, 27, 14, 6, 9, 29, 25, 31, 3, 10, 22, 30, 11, 19, 4, 12, 10, 6, 21, 27, 16, 22, 8, 32, 13, 6, 19, 30, 29, 26, 22, 2, 11, 8, 28, 17, 19, 10, 11, 19, 33, 23, 15, 12, 32, 31, 20, 5, 16, 11, 16, 4, 13, 24, 26, 18, 33, 14, 30, 33, 24, 19, 33, 19, 12, 27, 24, 29, 33, 13, 14, 10, 22, 25, 24, 32, 18, 5, 9, 6, 33, 27, 31, 26, 12, 16, 7, 30, 3, 12, 25, 11, 12, 28, 31, 5, 32, 13, 1, 5, 3, 26, 11, 25, 9, 28, 16, 3, 27, 13, 19, 18, 16, 12, 15, 18, 9, 4, 25, 6, 16, 14, 2, 10, 20, 22, 20, 20, 8, 7, 7, 5, 32, 30, 9, 27, 33, 22, 4, 13, 8, 6, 11, 18, 18, 27, 26, 27, 25, 15, 22, 16, 11, 13, 15, 25, 11, 29, 7, 3, 15, 26, 21, 27, 22, 29, 11, 16, 2, 25, 32, 24, 17, 11, 13, 15, 9, 33, 31, 14, 20, 22, 32, 4, 25, 13, 28, 33, 4, 9, 16, 20, 22, 6, 23, 7, 18, 30, 9, 12, 19, 32, 27, 33, 5, 22, 18, 9, 9, 6, 5, 5, 4, 4, 33, 16, 13, 5, 28, 24, 24, 6, 1, 14, 13, 12, 15, 10, 24, 22, 12, 10, 31, 33, 29, 24, 18, 18, 13, 25, 26, 32, 15, 3, 14, 14, 26, 19, 32, 15, 33, 33, 2, 6, 10, 24, 21, 21, 31, 31, 12, 22, 12, 6, 30, 32, 8, 16, 24, 26, 13, 13, 16, 5, 17, 26, 4, 4, 7, 27, 27, 5, 14, 24, 23, 32, 13, 3, 23, 10, 30, 23, 31, 30, 18, 25, 11, 24, 21, 7, 19, 13, 19, 4, 28, 22, 27, 2, 17, 12, 33, 32, 4, 25, 21, 23, 24, 7, 13, 21, 33, 7, 33, 31, 7, 20, 30, 13, 22, 19, 33, 16, 2, 20, 4, 31, 2, 31, 21, 12, 24, 23, 22, 2, 20, 19, 15, 2, 28, 4, 9, 30, 15, 13, 30, 4, 17, 24, 13, 32, 2, 12, 24, 24, 19, 11, 19, 6, 33, 2, 9, 26, 25, 16, 15, 24, 6, 15, 4, 28, 2, 3, 32, 18, 10, 2, 13, 24, 16, 13, 28, 28, 22, 33, 25, 21, 2, 5, 2, 21, 1, 8, 17, 2, 5, 18, 33, 29, 27, 20, 30, 27, 23, 25, 1, 8, 19, 33, 22, 30, 17, 24, 17, 7, 16, 16, 4, 25, 23, 4, 31, 12, 10, 30, 17, 17, 14, 4, 24, 10, 32, 13, 14, 15, 29, 17, 13, 7, 4, 21, 16, 23, 16, 2, 13, 12, 33, 23, 27, 33, 28, 15, 31, 25, 13, 12, 20, 14, 18, 18, 7, 31, 3, 31, 30, 33, 13, 6, 26, 13, 14, 33, 26, 4, 17, 13, 7, 15, 5, 18, 19, 24, 25, 15, 14, 33, 19, 26, 19, 16, 27, 20, 12, 6, 11, 6, 5, 17, 29, 17, 10, 25, 26, 10, 6, 8, 25, 5, 11, 11, 7, 32, 14, 2, 2, 32, 25, 12, 30, 20, 32, 18, 30, 19, 20, 30, 31, 11, 21, 13, 27, 22, 15, 9, 26, 4, 10, 4, 9, 2, 5, 5, 31, 14, 26, 32, 8, 30, 19, 16, 27, 6, 4, 12, 17, 18, 24, 13, 17, 16, 4, 5, 30, 11, 21, 21, 21, 4, 25, 26, 13, 2, 13, 2, 8, 32, 6, 12, 32, 9, 30, 15, 24, 11, 7, 26, 14, 10, 10, 22, 13, 28, 2, 21, 20, 19, 16, 1, 14, 16, 1, 26, 8, 3, 14, 4, 20, 1, 3, 21, 26, 25, 20, 1, 18, 17, 6, 16, 8, 17, 30, 24, 32, 9, 4, 24, 8, 23, 12, 28, 4, 32, 5 }; int k = 9931; System.out.println(sol.numSubarrayProductLessThanK(nums, k)); }}
转载地址：http://umniz.baihongyu.com/