by Xiaokang Zhang | Jan 18, 2017 | Algorithm & Data Structure
Roman to Integer Given a roman numeral, convert it to an integer. Input is guaranteed to be within the range from 1 to 3999. To solve this problem, let’s first take a look at all roman numbers. Roman Number Roman number has the following basic symbols: 1: I 5: V...
by Xiaokang Zhang | Jan 17, 2017 | Algorithm & Data Structure
Course Schedule Problem There are a total of n courses you have to take, labeled from 0 to n-1. Some courses may have prerequisites, for example to take course 0 you have to first take course 1, which is expressed as a pair: [0,1] Given the total number of courses and...
by Xiaokang Zhang | Jan 17, 2017 | Algorithm & Data Structure
Connected components problem Given n nodes label from 0 to n – 1 and a list of undirected edges (each edge is a pair of nodes), write a function to find the number of connected components in an undirected graph: You can assume that no duplicate edges will appear...
by Xiaokang Zhang | Jan 16, 2017 | Economics
在讨论中国制造业的时候,我们除了联想到低成本、大规模,还常常联想到他的高污染。我们从很早就知道,中国制造业的快速发展是以牺牲环境为你代价的,这个代价就是污染。将这条逻辑反过来推理就是,如果控制污染或者减少污染就会牺牲经济发展。这样的逻辑正确吗?是正确的,这样的顾虑也正是很多政策这不愿意努力治理污染的原因:经济发展才是衡量政绩的主要标准。但是控制污染怎样影响经济发展呢?这其中的逻辑链条如何打通?...
by Xiaokang Zhang | Jan 16, 2017 | Sociology
《乡土中国》这本书是费孝通在西南联大时期讲授“乡村社会学”时期的课程讲义。作者在书里提出了“乡土中国”的概念,并以这个概念为原点,从方方面面解读中国社会。在阅读这本书的时候,我们需要注意以下两点:...