zoukankan      html  css  js  c++  java
  • 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.

    Note:

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

    Approach #1. Math. [Java]

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

      

    Analysis:

    The idea is always keep an max-product-window less than K;

    Every time shift window by adding a new number on the right(j), if the product is greater than K, then try to reduce numbers on the left(i), untill the subarray product fit less than K again, (subarray could be empty);

    Each step introduces x new  subarrays, where x is the size of the current window (j - i + 1);

    Example:

    for window (5, 2), when 6 is ntroduced, it add 3 new subarray: (5, (2, (6)))

    Reference:

    https://leetcode.com/problems/subarray-product-less-than-k/discuss/108861/JavaC%2B%2B-Clean-Code-with-Explanation

    永远渴望,大智若愚(stay hungry, stay foolish)
  • 相关阅读:
    DigCSDN介绍首页
    相似qq的IM聊天应用源代码
    iOS单元測试:Specta + Expecta + OCMock + OHHTTPStubs + KIF
    struts2訪问servlet的API
    Reorg
    开源 免费 java CMS
    hdu1874 畅通project续(求最短路径)
    在64位系统下,指向int型的指针占的内存空间多大?
    linux中mv命令使用详解
    C语言中%d,%p,%u,%lu等都有什么用处
  • 原文地址:https://www.cnblogs.com/h-hkai/p/10658785.html
Copyright © 2011-2022 走看看