3.λ.形而下技术博客

问题

Java世界里构建项目用什么工具呢，ant，maven和gradle。maven非常流行， 原因无非是maven仓库和项目架构的约定。但是ant构建过程更加容易理解， 因为ant展示了所有的操作。gradle拥有基于groovy语言的DSL语言且继承了 maven仓库的思想所以笔者认为未来是属于gradle的。

MiniLisp是什么？

MiniLisp是一个只用几百行代码实现的Lisp。以下是实现的 基本特性。

• integers, symbols, cons cells,
• global variables,
• lexically-scoped local variables,
• closures,
• if conditional,
• primitive functions, such as +, =, <, or list,
• user-defined functions,
• a macro system,
• and a copying garbage collector.

Clojure branch 20081217

为啥要做这件事情呢？

1. Clojure是一门jvm语言，使用了asm。
2. branch 20081217是最初的版本便于研究。

题目概述

原题链接

Given an integer matrix, find the length of the longest increasing path 
From each cell, you can either move to four directions: left, right, up or down. You may NOT move diagonally or move outside of the boundary (i.e. wrap-around is not allowed).

example:
nums = [
  [9,9,4],
  [6,6,8],
  [2,1,1]
]
return 4

解决方法

我的Grails的环境是

grails -v
| Grails Version: 3.2.6
| Groovy Version: 2.4.7
| JVM Version: 1.8.0_71

题目概述

原题链接

Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two middle value.

Examples: 
 `[2,3,4]` , the median is 3

 `[2,3]`, the median is (2 + 3) / 2 = 2.5

Design a data structure that supports the following two operations:

- void addNum(int num) - Add a integer number from the data stream to the data structure. 
- double findMedian() - Return the median of all elements so far.   
For example:

addNum(1)
addNum(2)
findMedian() -> 1.5
addNum(3) 
findMedian() -> 2

python虚拟环境

从python3.5开始,使用venv创建虚拟环境已经成为官方推荐的方案。 查看官方文档，可以看到如果想要创建一个干净的虚拟环境。方式如下

python -m venv myenv

Cython

Cython不是CPython的简称，而是一种提升Python代码执行效率的解决方案。 据说一般达到30x。一会我们来看看是不是真的。这个技术对老鸟来说已经是好多 年前的了。但是很多情况下python用户真的用不上，所以不知道也无妨。

题目概述

原题链接

Given an integer array nums, return the number of range sums that lie in [lower, upper] inclusive.
Range sum S(i, j) is defined as the sum of the elements in nums between indices i and j (i ≤ j), inclusive.

Example:
Given nums = [-2, 5, -1], lower = -2, upper = 2,
Return 3.
The three ranges are : [0, 0], [2, 2], [0, 2] and their respective sums are: -2, -1, 2.

题目概述

原题链接

You are given an integer array nums and you
have to return a new counts array. 
The counts array has the property where counts[i] is 
the number of smaller elements to the right of nums[i].

Example:

Given nums = [5, 2, 6, 1]

To the right of 5 there are 2 smaller elements (2 and 1).
To the right of 2 there is only 1 smaller element (1).
To the right of 6 there is 1 smaller element (1).
To the right of 1 there is 0 smaller element.
Return the array [2, 1, 1, 0].