Your Instructors

Geoffrey Challen is the primary creator and maintainer of learncs.online.

Geoffrey authored the lesson content and homework problems, and created and maintains the backend systems that power the playgrounds, explanations, problems, and other interactive website content. You can find more details about the course infrastructure and more complete credits here.

However, in the years since the original materials were created, other students and faculty from the University of Illinois, students from other institutions, and learncs.online students have contributed to the learncs.online materials. All contributors are listed below, starting with verified instructors.

If you'd like to contribute, please get in touch!

Instructors

Geoffrey Challen

he, him, his

Personal Website

Full Profile

Kotlin

Java

924 contributions

Colleen Lewis

 

Kotlin

Java

326 contributions

Ellen Spertus

she, her, hers

Teaching Professor, Khoury College of Computer Sciences, Northeastern University

Personal Website

Full Profile

Kotlin

Java

44 contributions

Chris Taylor

he, him, his

Personal Website

Full Profile

Java

36 contributions

Teacher

Rohith Sanjay

 

Kotlin

Java

115 contributions

Carlos Inigo Fernandez

 

Java

41 contributions

Conor Cunningham

 

Java

37 contributions

Thomas Cai

 

Kotlin

Java

34 contributions

Miguel Fernandez

 

Kotlin

Java

30 contributions

Jackie Chan

 

Kotlin

Java

28 contributions

Tutor

Rachanon Petchoo

 

Java

22 contributions

Arnav Sethi

 

Java

21 contributions

Haosen Yao

 

Kotlin

Java

21 contributions

Carl Edwards

 

Java

21 contributions

Benjamin Chang

 

Kotlin

19 contributions

Jacob Chang

 

Kotlin

Java

19 contributions

Patrick Cunningham

 

Java

18 contributions

Ritvik Sood

 

Java

18 contributions

Aden Krakman

 

Java

17 contributions

Ying Chen

 

Java

17 contributions

Justin Bai

 

Kotlin

17 contributions

Rohan Gudipaty

 

Java

16 contributions

Hyunho Kim

 

Kotlin

Java

16 contributions

Assistant

Sam Erens

 

Kotlin

Java

15 contributions

Nancy Jia

 

Kotlin

Java

13 contributions

Tom Sui

 

Java

13 contributions

Alistair Forsyth

 

Kotlin

13 contributions

Yuxuan Chen

 

Java

12 contributions

Ruisong Li

 

Kotlin

Java

12 contributions

Kaan Yigit

 

Java

12 contributions

Michael Rheintgen

 

Kotlin

12 contributions

Boyang Sun

 

Java

11 contributions

Matt Twyman

 

Java

11 contributions

Maxwell Yang

 

Java

11 contributions

Elijah Mock

 

Kotlin

Java

11 contributions

Jay Chen

 

Java

11 contributions

Collin Fox

 

Java

10 contributions

Zijing Wei

 

Kotlin

Java

10 contributions

Zuhair Ali

 

Kotlin

Java

10 contributions

Kevin Liu

 

Java

10 contributions

Zainab Memon

 

Java

10 contributions

Saashin Subramaniam

 

Java

10 contributions

Sriya Mikkilineni

 

Java

9 contributions

Ben Clarage

 

Kotlin

Java

9 contributions

Niharika Bhattacharjee

 

Java

9 contributions

Carolyn Zeng

 

Kotlin

Java

9 contributions

Prith Balaji

 

Java

9 contributions

Jake Cumberland

 

Java

9 contributions

Christopher Sahyouni

 

Java

9 contributions

Cristian Flores

 

Java

8 contributions

Arghya Srivastav

 

Java

8 contributions

Anushree Tibrewal

 

Java

8 contributions

Nathaniel Zukowski

 

Java

8 contributions

Anagha Shenoy

 

Kotlin

8 contributions

Daniel Gutierrez

 

Java

8 contributions

Rohan Shah

 

Kotlin

8 contributions

Jason Cai

 

Kotlin

Java

8 contributions

Sunwoo Baek

 

Java

8 contributions

Maaheen Maajed

 

Kotlin

Java

7 contributions

Lexi Ippolito

 

Java

7 contributions

Adelia Solarman

 

Java

7 contributions

Alex Gong

 

Java

7 contributions

Meera Jagannathan

 

Java

7 contributions

Hrishikesh Kalyanaraman

 

Java

7 contributions

Justin Kim

 

Kotlin

Java

7 contributions

Brendan Biernacki

 

Java

7 contributions

Daniel Song

 

Kotlin

Java

7 contributions

Chris Whamond

 

Kotlin

Java

7 contributions

Kaiwen Mo

 

Java

7 contributions

Anirudh Kumar

 

Java

6 contributions

Grace Jia

 

Kotlin

Java

6 contributions

Diego Taveras

 

Kotlin

6 contributions

Ishika Awachat

 

Java

6 contributions

Zhuoang Tao

 

Kotlin

Java

6 contributions

Prem Dhoot

 

Java

6 contributions

Eugene Jang

 

Java

6 contributions

Anakin Dey

 

Java

6 contributions

Saagar Kolachina

 

Kotlin

Java

6 contributions

Ahmed Hasan

 

Kotlin

Java

6 contributions

Amirthavarshini Sureshbabu

 

Java

6 contributions

Henry Tang

 

Java

6 contributions

Arpit Bansal

 

Kotlin

Java

6 contributions

Helper

Jonathan You

 

Java

5 contributions

Delu Zhao

 

Java

5 contributions

Monica Para

 

Kotlin

Java

5 contributions

Amaan Mirza

 

Java

5 contributions

Mike Cheng

 

Kotlin

5 contributions

Harsh Deep

 

Java

5 contributions

Arjun Prabhu

 

Java

5 contributions

Zhilan Wang

 

Java

5 contributions

Sarah O'Sullivan

 

Java

5 contributions

Raul Higareda

 

Java

5 contributions

Utkarsh Prasad

 

Java

5 contributions

Aashi Tyagi

 

Java

5 contributions

Chinonso Chinonso

 

Kotlin

5 contributions

Jongwoo Jeon

 

Java

4 contributions

Anuprova Bhowmik

 

Kotlin

Java

4 contributions

Matt Yang

 

Java

4 contributions

Youngmin Jeon

 

Java

4 contributions

Leo Li

 

Java

4 contributions

Akul Gupta

 

Java

4 contributions

Freddy Platinus

 

Java

4 contributions

Gargi Balasubramaniam

 

Java

4 contributions

Samuel Schapiro

 

Java

4 contributions

Charlie Rivera

 

Java

4 contributions

Arnav Motwani

 

Kotlin

4 contributions

Ashley Wang

 

Java

4 contributions

Daniyal Rana

 

Java

4 contributions

Leena Abdelrahman

 

Java

4 contributions

Rahul Kalle

 

Java

4 contributions

Rylan Turner

 

Java

4 contributions

Larry Liao

 

Java

4 contributions

Zetai Liu

 

Java

4 contributions

Aditya Joshi

 

Java

4 contributions

Prerana Singh

she, her, hers

Full Profile

Java

4 contributions

Hania Dziurdzik

 

Kotlin

Java

4 contributions

Dj Figueiredo

 

Kotlin

4 contributions

Yiming Niu

 

Java

4 contributions

Haozhe Li

 

Java

4 contributions

Milosz Dabrowski

 

Java

3 contributions

James Rockey

 

Java

3 contributions

Ojas Upalekar

 

Java

3 contributions

Bernie Zhu

 

Java

3 contributions

Jane Liu

 

Java

3 contributions

Rachel Huang

 

Java

3 contributions

Ayaan Jabbar

 

Kotlin

3 contributions

Neel Khare

 

Java

3 contributions

Violetta Dabros

 

Java

3 contributions

Palak Purwar

 

Java

3 contributions

Samarth Taneja

 

Java

3 contributions

Serena Trika

 

Java

3 contributions

Yuhua Weng

 

Java

3 contributions

Anish Meka

 

Java

3 contributions

Apramey Hosahalli

 

Java

3 contributions

Aarav Mande

 

Java

3 contributions

Idrees Mohammed

 

Kotlin

Java

3 contributions

Daniel Rugutt

 

Java

3 contributions

Eduardo Martinez

 

Java

3 contributions

Lina Mei

 

Kotlin

3 contributions

Serlina Ku

 

Java

3 contributions

Sana Madhavan

 

Java

3 contributions

Alyssa Daniels

 

Java

3 contributions

Preston Chao

 

Java

3 contributions

Warren Li

 

Java

3 contributions

Ananya Subramanian

 

Java

3 contributions

Kushal Agarwal

 

Java

3 contributions

Zhaoyang Chen

 

Kotlin

3 contributions

Yu He

 

Java

3 contributions

David Ruvinskiy

 

Kotlin

3 contributions

Aditi Khanna

 

Java

3 contributions

Archna Sobti

 

Java

3 contributions

Savannah Holly

 

Java

3 contributions

Anish Thiriveedhi

 

Java

3 contributions

Joy Wan

 

Java

3 contributions

Jainil Modi

 

Java

3 contributions

Vansh Sikka

 

Java

3 contributions

Vansh Gupta

 

Java

3 contributions

Will Otani

 

Java

3 contributions

Havish Rani

 

Java

3 contributions

Lenna Park

 

Java

3 contributions

Ananyaa Tanwar

 

Java

3 contributions

Meghna Mavila

 

Java

3 contributions

Josh Joseph

 

Java

3 contributions

Wendy Ruan

 

Java

3 contributions

Nishit Samarth

 

Java

3 contributions

Chengze Shen

 

Java

3 contributions

Becky Blake

 

Java

3 contributions

Gabriel Grais

 

Java

3 contributions

Juyoung Choi

 

Java

3 contributions

Qingping Ye

 

Java

3 contributions

Kavin Krishnasami

 

Java

3 contributions

Helen Ilkiu

 

Java

3 contributions

Athena Fung

 

Java

3 contributions

Tyler Cushing

 

Kotlin

3 contributions

David Yang

 

Java

3 contributions

Di Liang

 

Java

3 contributions

Andrew Kim

 

Kotlin

3 contributions

Eric Ji

 

Java

3 contributions

Chris Munoz

 

Java

3 contributions

Joseph Dubravec

 

Java

3 contributions

Meghna Gaddam

 

Java

3 contributions

Martina Perez Zuleta

 

Java

3 contributions

Andrew Lum

 

Java

3 contributions

Jenny Yang

 

Java

3 contributions

Eunice Leung

 

Java

3 contributions

Tianyun Zhang

 

Java

3 contributions

Elisa Carrillo

 

Java

3 contributions

Louis Qian

 

Java

3 contributions

Ishq Gupta

 

Java

3 contributions

Jier Miao

 

Java

3 contributions

Elijah Song

 

Kotlin

3 contributions

Bilal Karim

 

Java

3 contributions

Junhao Xiong

 

Java

3 contributions

Mick Enev

 

Java

3 contributions

Matthew McCarthy

 

Kotlin

3 contributions

Lexi Guan

 

Java

3 contributions

Ethan Sirois

 

Kotlin

3 contributions

Alekhya Nathella

 

Java

2 contributions

Harshit Bagla

 

Java

2 contributions

Daniel Dilan

 

Java

2 contributions

Sarod Nori

 

Java

2 contributions

Samuel Hurh

 

Java

2 contributions

Ayah Jaber

 

Java

2 contributions

Adrian Russo

 

Java

2 contributions

Shao-Min Yeh

 

Java

2 contributions

Janani Jayanth

 

Java

2 contributions

Rohan Sathe

 

Java

2 contributions

Alex Che

 

Java

2 contributions

Jake Vile

 

Java

2 contributions

Tanay Pareek

 

Java

2 contributions

Kangyu Feng

 

Java

2 contributions

Ken Kim

 

Java

2 contributions

Brandon Dinh

 

Java

2 contributions

Ishan Khandelwal

 

Java

2 contributions

Tina Dou

 

Java

2 contributions

Emmanuel Buabeng

 

Java

2 contributions

Yiche Liu

 

Java

2 contributions

Alma Zirojevic

 

Java

2 contributions

Anna Fedczuk

 

Java

2 contributions

Armin Rafieyan

 

Kotlin

2 contributions

Anna Liu

 

Java

2 contributions

Vaibhav Keshari

 

Kotlin

2 contributions

Allen Guo

 

Java

2 contributions

Rahul Bhatt

 

Java

2 contributions

Brenda Hariyanto

 

Java

2 contributions

Abhi Vinnakota

 

Java

2 contributions

Ruozhen Yang

 

Java

2 contributions

Edmon Guan

 

Java

2 contributions

Sabrina Tu

 

Java

2 contributions

Joseph Chan

 

Java

2 contributions

Dawn Lim

 

Kotlin

2 contributions

Yasmine Munoz

 

Java

2 contributions

Tianyi Huang

 

Java

2 contributions

Cloud Li

 

Java

2 contributions

Zoe Lu

 

Java

2 contributions

Srikar Manikonda

 

Java

2 contributions

Yuan Ochoa

 

Java

2 contributions

Yanze Lu

 

Java

2 contributions

Vish Ganesan

 

Kotlin

2 contributions

Kelly Chen

 

Java

2 contributions

Grace Cho

 

Java

2 contributions

Jared Buabeng

 

Java

2 contributions

Nathan Liu

 

Java

2 contributions

Manasi Vaidya

 

Java

2 contributions

Max Jing

 

Kotlin

Java

2 contributions

Elizabeth Spencer

 

Kotlin

2 contributions

Steven Salisbury

 

Kotlin

2 contributions

Lou Zeh

 

Java

1 contribution

Juan David Campolargo Hoyos

 

Java

1 contribution

Ethan Miranda

 

Kotlin

1 contribution

Mayank Hirani

 

Java

1 contribution

Aditya Shreenivas Kunte

 

Java

1 contribution

Siddharth Tangri

 

Java

1 contribution

Vinayak Manepalli

 

Java

1 contribution

Varun Shroff

 

Java

1 contribution

Rohan Khatu

 

Java

1 contribution

Adrian Rodriguez

 

Java

1 contribution

Tongyun Huang

 

Java

1 contribution

Shruthi Jaganathan

 

Java

1 contribution

Nicholas Jung

 

Java

1 contribution

Dazhen Chen

 

Java

1 contribution

Cindy Su

 

Java

1 contribution

Jason Wu

 

Java

1 contribution

Ricky Chen

 

Java

1 contribution

Jason Barnett

 

Kotlin

1 contribution

Anish Jampana

 

Java

1 contribution

Siyuan Ding

 

Java

1 contribution

Aadarsh Krishnan

 

Java

1 contribution

Matthew Czech

 

Java

1 contribution

Raghav Anand

 

Java

1 contribution

Edward Huang

 

Java

1 contribution

Meghan Lu

 

Java

1 contribution

Jimmy Berg

 

Kotlin

1 contribution

Aryan Vakharia

 

Java

1 contribution

Connor Flynn

 

Java

1 contribution

Aaron Taub

 

Java

1 contribution

Nehal Tangudu

 

Java

1 contribution

Anisha Raja

 

Java

1 contribution

Thomas Zelichowski

 

Java

1 contribution

Saurav Chittal

 

Java

1 contribution

Blair Wang

 

Java

1 contribution

Keshav Trikha

 

Java

1 contribution

Jessica Ho

 

Java

1 contribution

Hamiz Anjum

 

Java

1 contribution

Simon Li

 

Java

1 contribution

Ziyin Wang

 

Java

1 contribution

Ram Goenka

 

Java

1 contribution

Ryan Wang

 

Kotlin

1 contribution

Shoorsen Gandhi

 

Kotlin

1 contribution

Joe Tamulaitis

 

Kotlin

1 contribution

Tracy Li

 

Kotlin

1 contribution

Panyue Chen

 

Java

1 contribution

Jiaqi He

 

Java

1 contribution

Punn Pinkayan

 

Java

1 contribution

Wentao Qi

 

Java

1 contribution

Ishaan Bhandari

 

Java

1 contribution

Student Contributors

The following students have contributed explanations to learncs.online, which have been approved by instructors and now appear on the website:

Jorge R.

 

Java

5 contributions

Ayesha Ahmed

 

Java

1 contribution

Jo Ma Me

 

Java

1 contribution

Sisa Pallchisaca

 

Java

1 contribution

Nathan Chen

 

Kotlin

1 contribution

Chinasa Nwosu

 

Java

1 contribution

Michal Lampejo

 

Java

1 contribution

Aisha Salau

 

Java

1 contribution

KJ _Sodipe

 

Java

1 contribution

Daniel Lopez

 

Java

1 contribution

Chris Perfecto

 

Kotlin

1 contribution

Valeria Horta

 

Java

1 contribution

Symone Williams

 

Java

1 contribution

Jaylen Moreira

 

Java

1 contribution

Nazir McBride

 

Java

1 contribution

Charlotte Bright

 

Kotlin

1 contribution

Waad Idriss

 

Java

1 contribution

Kent Anderson

 

Java

1 contribution

I don't even know

 

Kotlin

1 contribution

owusu peprah

 

Java

1 contribution

Karina Martinez

 

Java

1 contribution

David Cano

 

Java

1 contribution

Emmanuel Oginni

 

Java

1 contribution

Question Authors

Questions on the lessons and practice page were authored by the following contributors:

Geoffrey Challen

 

Kotlin

Java

396 questions
(376 Kotlin, 396 Java)

Justin Maier

 

Java

49 questions
(0 Kotlin, 49 Java)

Chris Taylor

 

Kotlin

Java

36 questions
(2 Kotlin, 36 Java)

Ellen Spertus

 

Java

14 questions
(0 Kotlin, 14 Java)

Miguel Fernandez

 

Kotlin

Java

2 questions
(2 Kotlin, 2 Java)

Harsh Deep

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

Ayesha Ahmed

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

CEO

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

Michal Lampejo

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

Giovanni Pastor

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

Aisha Salau

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)

Nikita Neledov

 

Kotlin

Java

1 question
(1 Kotlin, 1 Java)