Skip to content

Latest commit

 

History

History
125 lines (96 loc) · 3.85 KB

arts-0012.md

File metadata and controls

125 lines (96 loc) · 3.85 KB
Raw

1.Algorithm

[11]  Container With Most Water

Easy    array    two pointers

Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of the line i is at (i, ai) and (i, 0). Find two lines, which, together with the x-axis forms a container, such that the container contains the most water.

Notice that you may not slant the container.

Example2:

Input: height = [1,1]
Output: 1

Example3:

Input: height = [4,3,2,1,4]
Output: 16

Example4:

Input: height = [1,2,1]
Output: 2

解答 本题可以采用常规的方法和基于 hashtab 的方式进行处理(题目描述中已经定义不存在重复的数据)

(1).直接处理，两层 for 迭代，时间复杂度为 O(n*n)
func maxArea(height []int) int {
	max := 0
	for i := 0; i < len(height); i++ {
		for j := i + 1; j < len(height); j++ {
			minVal, interval := height[i], j-i
			if height[j] < minVal {
				minVal = height[j]
			}
			total := minVal * interval
			if total > max {
				max = total
			}
		}
	}
	return max
}
(2)采用双指针方式，减少一层 for 迭代，时间复杂度为 O(n)
func maxArea(height []int) int {
	max, left, right := 0, 0, len(height)-1
	for left < right {
		minVal, interval := height[left], right-left
		if height[right] < minVal {
			minVal = height[right]
		}
		total := minVal * interval
		if total > max {
			max = total
		}

		if height[left] < height[right] {
			left++
		} else {
			right--
		}
	}
	return max
}

2.Review

Advice to Myself When Starting Out as as Software Developer

  1. Take the time to read two books per year on software engineering
  2. Learn the language you use at work in-depth, to the very bottom

    (1). The more languages you know, the more you can evaluate their strengths and weaknesses.

  3. Pair with other developers more often
  4. Write unit tests and run them against a CI
  5. Make refactoring a habit and master refactoring tools
  6. Know that good software engineering is experience. Get lots of it.

    (2). Look for opportunities to work on different stacks, different domains, and challenging projects.

  7. Teach what you learn

3.Tip

这周看了一些有关 Web IM 方面有关消息推送的资料，但是看的还不深入，通知方案主要有以下几种： 在线客服系统最重要的就是通知，用户发送的消息如何通知客服，客服发送的消息又如何通知用户？

  • 轮询：客户端定时刷新，采用 ajax 方式在后台定时获取数据。
优点：实现简单，无需做过多的更改
缺点：轮询的间隔过长，会导致用户不能及时接收到更新的数据；轮询的间隔过短，会导致查询请求过多，增加服务器端的负担
  • 长连接：客户端向服务器端发起请求的时候，服务端会阻塞请求，知道服务器端读取到消息才返回
优点：比 polling 做了优化，有较好的时效性
缺点：保持连接会消耗资源；服务器没有返回有效数据，程序超时。
  • websocket: 服务器端可以主动推送消息给客户端
支持双向通信，实时性更强
可以发送文本，也可以发送二进制数据
减少通信量：只要建立起WebSocket连接，就希望一直保持连接状态。和HTTP相比，不但每次连接时的总开销减少，而且由于WebSocket的首部信息很小，通信量也相应减少了

4.Share

My Reading & Listening List 这篇文章分享了有关软件开发和管理方面的一些书籍，特别是 Podcasts 这部分，里面有些非常好的 podcasts 频道资源。