Files
2020-08-09 00:39:24 +08:00

46 lines
3.6 KiB
Markdown
Executable File
Raw Permalink Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# [1052. Grumpy Bookstore Owner](https://leetcode.com/problems/grumpy-bookstore-owner/)
## 题目
Today, the bookstore owner has a store open for `customers.length`minutes. Every minute, some number of customers (`customers[i]`) enter the store, and all those customers leave after the end of that minute.
On some minutes, the bookstore owner is grumpy. If the bookstore owner is grumpy on the i-th minute, `grumpy[i] = 1`, otherwise `grumpy[i] = 0`. When the bookstore owner is grumpy, the customers of that minute are not satisfied, otherwise they are satisfied.
The bookstore owner knows a secret technique to keep themselves not grumpy for `X` minutes straight, but can only use it once.
Return the maximum number of customers that can be satisfied throughout the day.
**Example 1:**
Input: customers = [1,0,1,2,1,1,7,5], grumpy = [0,1,0,1,0,1,0,1], X = 3
Output: 16
Explanation: The bookstore owner keeps themselves not grumpy for the last 3 minutes.
The maximum number of customers that can be satisfied = 1 + 1 + 1 + 1 + 7 + 5 = 16.
**Note:**
- `1 <= X <= customers.length == grumpy.length <= 20000`
- `0 <= customers[i] <= 1000`
- `0 <= grumpy[i] <= 1`
## 题目大意
今天书店老板有一家店打算试营业 customers.length 分钟。每分钟都有一些顾客customers[i])会进入书店,所有这些顾客都会在那一分钟结束后离开。在某些时候,书店老板会生气。 如果书店老板在第 i 分钟生气,那么 grumpy[i] = 1否则 grumpy[i] = 0。 当书店老板生气时那一分钟的顾客就会不满意不生气则他们是满意的。书店老板知道一个秘密技巧能抑制自己的情绪可以让自己连续 X 分钟不生气,但却只能使用一次。请你返回这一天营业下来,最多有多少客户能够感到满意的数量。
提示:
1. 1 <= X <= customers.length == grumpy.length <= 20000
2. 0 <= customers[i] <= 1000
3. 0 <= grumpy[i] <= 1
## 解题思路
- 给出一个顾客入店时间表和书店老板发脾气的时间表。两个数组的时间是一一对应的,即相同下标对应的相同的时间。书店老板可以控制自己在 X 分钟内不发火,但是只能控制一次。问有多少顾客能在书店老板不发火的时候在书店里看书。抽象一下,给出一个价值数组和一个装着 0 和 1 的数组,当价值数组的下标对应另外一个数组相同下标的值是 0 的时候,那么这个价值可以累加,当对应是 1 的时候,就不能加上这个价值。现在可以让装着 0 和 1 的数组中连续 X 个数都变成 0问最终价值最大是多少
- 这道题是典型的滑动窗口的题目。最暴力的解法是滑动窗口右边界,当与左边界的距离等于 X 的时候,计算此刻对应的数组的总价值。当整个宽度为 X 的窗口滑过整个数组以后,输出维护的最大值即可。这个方法耗时比较长。因为每次计算数组总价值的时候都要遍历整个数组。这里是可以优化的地方。
- 每次计算数组总价值的时候,其实目的是为了找到宽度为 X 的窗口对应里面为 1 的数累加和最大,因为如果把这个窗口里面的 1 都变成 0 以后,那么对最终价值的影响也最大。所以用一个变量 `customer0` 专门记录脾气数组中为 0 的对应的价值,累加起来。因为不管怎么改变,为 0 的永远为 0唯一变化的是 1 变成 0 。用 `customer1` 专门记录脾气数组中为 1 的对应的价值。在窗口滑动过程中找到 `customer1` 的最大值。最终要求的最大值就是 `customer0 + maxCustomer1`