Google Codejam 15 - Standing Ovation - simle problem explained simply

Event:
Google Codejam 2015 
Qualification Round 
Problem A : Standing Ovation
Link: https://code.google.com/codejam/contest/6224486/dashboard#s=p0

You advised to go through the problem in above link or read it at the bottom of this blog post.

Oracle Certified Java Professional :)

After giving SCJP(yea was thinking since then) study a start for about 3 times, since last 2 years, I have now completed the Oracle Certified Java Professional Certification.

Java memory analysis using inbuilt tools

jhat(Heap Analysis Tool) is a tool that comes along with the jdk and is present under jdkxxx/bin/ .

There are two way to get the heap dump

1. Give it while starting the java program as
java -Xrunhprof:format=b,file=file.hprof class-name
2. Get the heap dump using jmap as

jmap -dump:file=file-name process_id

Here I am using the first method. The java code ran is the same as described in this post about Thread-Creation-Time.

Java analyzing thread creation time

In Java, the thread creation time increases with the number of thread that are already created, hence it is advisable to keep the thread count minimal and only create a Thread when actually needed.

The below gist is a minimal piece of java code that helps in proving this