What are carriage return, linefeed, and form feed?

https://stackoverflow.com/questions/3091524/what-are-carriage-return-linefeed-and-form-feed

“What Are Carriage Return, Linefeed, and Form Feed?” Newline - What Are Carriage Return, Linefeed, and Form Feed? - Stack Overflow, stackoverflow.com/questions/3091524/what-are-carriage-return-linefeed-and-form-feed.

背包问题九讲

http://love-oriented.com/pack/

“背包问题九讲.” 背包问题九讲, love-oriented.com/pack/. Accessed 5 July 2017.

About Multi-thread

https://www.jiuzhang.com/qa/2232/

“关于多线程？.” 问答 | 九章算法, www.jiuzhang.com/qa/2232/. Accessed 5 July 2017.

Movie score prediction in IMDB 5000 movie dataset

https://www.kaggle.com/yifengzeng/imdb-5000-movie-score-prediction/

https://gist.github.com/YifengZeng/94a902467036e6c00034acf3da219141

echo SGVsbG8gZnJvbSBZaWZlbmcK | base64 -D

Java - why doesn't ArrayList as key in HashMap work?

https://stackoverflow.com/questions/35560067/why-doesnt-arraylist-as-key-in-hashmap-work

“Why Doesn't ArrayList as Key in HashMap Work?” Java - Why Doesn't ArrayList as Key in HashMap Work? - Stack Overflow, stackoverflow.com/questions/35560067/why-doesnt-arraylist-as-key-in-hashmap-work. Accessed 14 June 2017.

Binary Tree Postorder Traversal

	/**
	* Definition of TreeNode:
	* public class TreeNode {
	* public int val;
	* public TreeNode left, right;
	* public TreeNode(int val) {
	* this.val = val;
	* this.left = this.right = null;
	* }
	* }
	*/
	public class Solution {
	/**
	* @param root: The root of binary tree.
	* @return: Postorder in ArrayList which contains node values.
	*/
	public ArrayList<Integer> postorderTraversal(TreeNode root) {
	// write your code here
	ArrayList<Integer> res = new ArrayList<>();
	if (root == null) {
	return res;
	}
	Deque<TreeNode> stack = new ArrayDeque<>();
	stack.push(root);
	TreeNode cur = root;
	while (!stack.isEmpty()) {
	TreeNode node = stack.peek();
	if (node.left == null && node.right == null ||
	node.left == cur || node.right == cur) {
	cur = stack.pop();
	res.add(cur.val);
	} else {
	if (node.right != null) {
	stack.push(node.right);
	}
	if (node.left != null) {
	stack.push(node.left);
	}
	}
	}
	return res;
	}
	}

view raw postorderTraversal.java hosted with ❤ by GitHub

Does Java pass by reference or pass by value?

http://www.javaworld.com/article/2077424/learn-java/does-java-pass-by-reference-or-pass-by-value.html

Sintes, Tony. “Does Java Pass by Reference or Pass by Value?” JavaWorld, JavaWorld, 26 May 2000, www.javaworld.com/article/2077424/learn-java/does-java-pass-by-reference-or-pass-by-value.html. Accessed 8 Apr. 2017.

Operation latency

From:
https://fusiontables.google.com/DataSource?snapid=S523155yioc
Latency numbers every programmer should knowJeff Dean (http://research.google.com/people/jeff/)

operation   latency (ns)

L1 cache reference 0.5 Branch mispredict 5 L2 cache reference 7 Mutex lock/unlock 25 Main memory reference 100 Compress 1K bytes with Zippy 3,000 Send 2K bytes over 1 Gbps network 20,000 Read 1 MB sequentially from memory 250,000 Round trip within same datacenter 500,000 Disk seek 10,000,000 Read 1 MB sequentially from disk 20,000,000 Send packet CA->Netherlands->CA 150,000,000

Set, HashSet, Map, HashMap, TreeSet, TreeMap

https://teamtreehouse.com/community/set-hashset-map-hashmap-treeset-treemap

“Set, HashSet, Map, HashMap, TreeSet, TreeMap.” Set, HashSet, Map, HashMap, TreeSet, TreeMap | Treehouse Community, teamtreehouse.com/community/set-hashset-map-hashmap-treeset-treemap. Accessed 23 Mar. 2017.

An article about HBase, Cassandra & MongoDB comparison from LinkedIn

https://www.linkedin.com/pulse/real-comparison-nosql-databases-hbase-cassandra-mongodb-sahu

Hadoop FS/DFS

https://dzone.com/articles/difference-between-hadoop-dfs
Jain, Abhishek. “The Difference Between 'Hadoop DFS' and 'Hadoop FS' - DZone Big Data.” Dzone.com, 25 Dec. 2015, dzone.com/articles/difference-between-hadoop-dfs. Accessed 21 Mar. 2017.

Master-Master vs Master-Slave Database Architecture

http://stackoverflow.com/questions/3736969/master-master-vs-master-slave-database-architecture

“Master-Master vs Master-Slave Database Architecture?” Stack Overflow, stackoverflow.com/questions/3736969/master-master-vs-master-slave-database-architecture. Accessed 21 Mar. 2017.

HashMap vs HashTable

http://stackoverflow.com/questions/40471/differences-between-hashmap-and-hashtable

“Differences between HashMap and Hashtable?” Java - Differences between HashMap and Hashtable? - Stack Overflow, stackoverflow.com/questions/40471/differences-between-hashmap-and-hashtable. Accessed 16 Mar. 2017.

List vs ArrayList

http://stackoverflow.com/questions/9852831/polymorphism-why-use-list-list-new-arraylist-instead-of-arraylist-list-n

“Polymorphism: Why Use ‘List List = New ArrayList’ Instead of ‘ArrayList List = New ArrayList’?” Java - Polymorphism: Why Use "List List = New ArrayList" Instead of "ArrayList List = New ArrayList"? - Stack Overflow, stackoverflow.com/questions/9852831/polymorphism-why-use-list-list-new-arraylist-instead-of-arraylist-list-n. Accessed 11 Mar. 2017.

“Converting 'ArrayList to 'String[]' in Java.”

http://stackoverflow.com/questions/4042434/converting-arrayliststring-to-string-in-java

“Converting 'ArrayList to 'String[]' in Java.” Arrays - Converting 'ArrayList to 'String[]' in Java - Stack Overflow, stackoverflow.com/questions/4042434/converting-arrayliststring-to-string-in-java. Accessed 11 Mar. 2017.

P/NP/NPC

http://www.matrix67.com/blog/archives/105

“Matrix67: The Aha Moments.” Matrix67 The Aha Moments, www.matrix67.com/blog/archives/105. Accessed 10 Mar. 2017.

Static class in Java

http://www.geeksforgeeks.org/static-class-in-java/

“Static Class in Java.” GeeksforGeeks, 24 Feb. 2014, www.geeksforgeeks.org/static-class-in-java/. Accessed 23 Feb. 2017.

Stack

http://www.ruanyifeng.com/blog/2013/11/stack.html

“Stack的三种含义.” Stack的三种含义 - 阮一峰的网络日志, www.ruanyifeng.com/blog/2013/11/stack.html. Accessed 18 Feb. 2017.

An article about Google Spanner

www.wired.com/2012/11/google-spanner-time

Metz, Cade. “Exclusive: Inside Google Spanner, the Largest Single Database on Earth.” Wired, Conde Nast, 26 Nov. 2012, www.wired.com/2012/11/google-spanner-time/. Accessed 18 Feb. 2017.

Hadoop shuffle phase

Cite from http://www.cnblogs.com/edisonchou/p/4298423.html

“Edison Chou.” Hadoop学习笔记-10.Shuffle过程那点事儿 - Edison Chou - 博客园, www.cnblogs.com/edisonchou/p/4298423.html.

The difference between String, StringBuffer and StringBuilder

Cite from http://blog.csdn.net/kingzone_2008/article/details/9220691

“Java：String、StringBuffer和StringBuilder的区别.” Java：String、StringBuffer和StringBuilder的区别 - __kingzone__的专栏 - 博客频道 - CSDN.NET, blog.csdn.net/kingzone_2008/article/details/9220691.

wordCount template

	/**
	* Created by Yifeng Zeng on 2/14/17.
	*/
	import java.io.IOException;
	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.fs.Path;
	import org.apache.hadoop.io.IntWritable;
	import org.apache.hadoop.io.Text;
	import org.apache.hadoop.mapreduce.Job;
	import org.apache.hadoop.mapreduce.Mapper;
	import org.apache.hadoop.mapreduce.Reducer;
	import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
	import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
	public class WordCount {
	public static class TokenizerMapper extends Mapper<Object, Text, Text, IntWritable> {
	enum WordList{
	Big,
	Data,
	Love,
	OTHER
	}
	@Override
	public void map(Object key, Text value, Context context)
	throws IOException, InterruptedException {
	//key: offset
	//value: line
	//value: I love big data
	String[] words = value.toString().replaceAll("[,.;]", "").trim().split(" ");
	for (String word : words) {
	// I=1, love=1, big=1, data=1
	Text outKey = new Text(word);
	IntWritable outValue = new IntWritable(1);
	context.write(outKey, outValue);
	if (word.toLowerCase().equals("big")) {
	context.getCounter(WordList.Big).increment(1);
	} else if (word.toLowerCase().equals("data")) {
	context.getCounter(WordList.Data).increment(1);
	} else if (word.toLowerCase().equals("love")) {
	context.getCounter(WordList.Love).increment(1);
	} else {
	context.getCounter(WordList.OTHER).increment(1);
	}
	context.getCounter("wordCount", word).increment(1);
	}
	}
	}
	public static class IntSumReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
	@Override
	public void reduce(Text key, Iterable<IntWritable> values, Context context)
	throws IOException, InterruptedException {
	//I <1>
	//big <1, 1>
	int sum = 0;
	for (IntWritable value : values) {
	sum += value.get();
	}
	context.write(key, new IntWritable(sum));
	}
	}
	public static void main(String[] args) throws Exception {
	Configuration configuration = new Configuration();
	Job job = new Job(configuration, "wordCount");
	job.setJarByClass(WordCount.class);
	job.setMapperClass(TokenizerMapper.class);
	job.setReducerClass(IntSumReducer.class);
	job.setOutputKeyClass(Text.class);
	job.setOutputValueClass(IntWritable.class);
	FileInputFormat.addInputPath(job, new Path(args[0]));
	FileOutputFormat.setOutputPath(job, new Path(args[1]));
	job.waitForCompletion(true);
	}
	}

view raw WordCount.java hosted with ❤ by GitHub