Challenge #307: Round-robin

A solution to last week’s challenge can be found here.

Weekly Challenge Image 307.png You and your friends have decided to start your own tennis league. Your friends know you are good with data and have put you in charge of creating the schedule for the season.

At this point, you don’t know how many teams will be joining the league or how long the season will last. You decide to create an app that has two inputs: the number of teams participating and the number of weeks for the season. The app will then create a round robin schedule where each team will be matched up with each other team an equal number of times (unless the inputs require bye weeks).

The "Output Sample" shows what your output data rows will look like if you have 5 teams and 5 weeks for example.

Weekly Challenge 307_Start File.yxzp

Weekly Challenge 307_Solution File Corrected.yxzp

Macros

Apps

Advanced

Intermediate

Interface

Accepted answers

All comments

joelmiller66

Spoiler

Weekly Challenge 307_JM_ABDC.yxwz

balajilolla1

Spoiler

Solution Attached

Round Robin.yxzp

TonyA

Here's my solution.

Spoiler

The round robin pattern in the solution had Team A starting with 1 one in the first match and other matches in the week with 2, 3, 4 etc. The second week starting with team 2 and so on, wrapping back to 1 after the max team. Team B started with the highest number team the first week in the first match and counting down for the successive matches in that week, wrapping back to the max team number after 1. Then started the second week with Max - 1 and so on. Turns out this does give a balanced number of matches for each pair of teams and the same number of games for every team assuming the number of weeks is a multiple of the number of teams. If not some of the teams might get one more game than others.

Weekly Challenge 307_TonyA.yxwz

RolandSchubert

Spoiler

Great challenge! Used an iterative macro to create the the schedule.

Hilda

My Solution.

Spoiler

WC_307_Round_robin.yxwz

Qiu

Hope I get it right.

Spoiler

Weekly Challenge 307_Start File-qIU.yxzp

AkimasaKajitani

My solution.

Spoiler

I was not sure how to handle the number of the season. So, I make the Round Robin schedule then I update the Weeks by considering the number of the season.

Weekly Challenge 307_Start File_AK.yxwz

patrick_digan

Fun! Just another challenge that I found a way to overcomplicate...

Spoiler

I wanted to first find all the possible matchups (ie team 1 vs team 2, team 1 vs team 3 etc.) for each week (ie 1-2 and 3-4 could be week 1's matchups). Then I basically cartesian joined that for the number of weeks that are played. This is a really big dataset with all possible matchups. I then found the average number of distinct matchups and picked the first one. It took 2 iterative macros and way too many tools, but this is how my brain was able to think through it.

Weekly Challenge 307_Start File.yxzp

Nelson_D

Hi All,

Attached is my solution.

Spoiler

Thanks

D Nelson

Weekly Challenge 307_Nelson.yxwz

NikyN

Here is my solution 😊

Challenge 307 - Round-Robin - NikyN.yxwz

tammybrown_tds

@RolandSchubert,

Care to share your workflow (including the iterative macro)? I'm stuck on how to make this work with anything but 5 teams and 5 weeks. I downloaded everyone else's solutions for inspiration, and none of them work. All of them are good for only 5 teams and 5 weeks.

Yours appears to work, based on the pictures you posted, but you didn't attached your workflow. Was hoping to review how you did it now that I've spent way too many hours trying to figure it out on my own.

RolandSchubert

Thank you @tammybrown_tds for pointing this out, I actually forgot to attach the workflow.

Weekly Challenge 307_solution_rsc.yxzp

alexnajm

Tough one!

Spoiler

Weekly Challenge 307_Start File_Alex Abi-Najm.yxwz

tammybrown_tds

This was fun, once I found some inspiration to get the app to work the way that I wanted it to. Thanks @RolandSchubert!

Spoiler

challenge_307_tbrown.yxwz

SG_1997

Hello Team,

Spoiler

Weekly Challenge 307.yxwz

kelvin_law1

Here is my solution:

Spoiler

Weekly Challenge 307_Solution.yxwz

Kenda

Spoiler

It was fun turning this real-world problem I had into a weekly challenge!
I completed mine in vertical, of course.

Round Robin Scheduler App.yxzp

Charlesswinehart

Spoiler

Fun Challenge

Weekly Challenge 307_Completed.yxwz

KilianL

As quick as possible: generating unique matches and my favorite: tile tool magic to assign weeks.

Spoiler

307 - Round Robin - Kilian.yxwz

Watermark

Spoiler

Here's an extra hint for you : https://en.wikipedia.org/wiki/Round-robin_tournament#Circle_method

MT Solution 307.jpg

Works regardless the number of players or weeks. It also accounts for 'odd' number of players to create 'bye' weeks.

MT Solution 307 Result.jpg

challenge_307_MT_solution Macro.yxmc

Weekly Challenge 307_MT_Solution.yxmd

Charlesswinehart

While looking through workflows and testing yours, I found that our outputs are nearly identical even though our initial workflows are very different.

Upon further inspection I found that my workflow works great with an odd number of teams, but falls apart completely(with duplicate matching) when an even number of teams is used. I was able to fix it to work properly with even teams by first identifying if the number of teams is even or odd, then, if even, removing one team, doing the combinations as if there were only (N-1) teams, then instead of filtering out results where Team A = Team B, change Team B to = Team N, and end up with completely unique results. IE. instead of filtering out "Bye" weeks the Bye week gets automatically matched with team N.

This also means odd teams need N weeks to have a "perfect" number of weeks to complete all combinations but even number of teams only need N-1 weeks to complete all combinations!

I've included a reference from the Wikipedia article about round robin tournaments to visually represent what the workflow is doing with Team 10 in a 10 team scenario

Spoiler

Milanz

my solution ;-)

Spoiler

Weekly Challenge 307_ML.yxwz

messi007

Spoiler

Weekly Challenge 307_Solution File.yxwz

tammybrown_tds

@Kenda,

Can you tell me how the posted solution is correct? If I run the solution with 5 teams and 15 weeks (which would be the number of weeks required for each team to play each of the other teams exactly three times, I get this:

This output only considers 3 teams (Teams 4 & 5 never play) and only one Team A vs Team B matchup per week.

It should have 50 rows where something like this is repeated 5 times (weeks 1-5; 6-10; 11-15):

How does the solution imitate a round-robin schedule?

Kenda

Hi @tammybrown_tds

It seems as though the wrong version was uploaded as the solution. I will upload a corrected version later, but in the meantime, change the Condition Expression in the Generate Rows tool to:

teams <= tonumber("%Question.teams%")

Currently, it is set to always equal 3 which is why you're seeing those results.

Kenda

Spoiler

Updated workflow and iterative macro!

Weekly Challenge 307_v2.yxzp

binu_acs

Spoiler

Weekly Challenge 307_Solution_BV.yxwz

philipmannering

Spoiler

Challenge 307 - Round Robin.yxwz

leozhang2work

Spoiler

As I was just doing AC #247 today as well, which asks for pretty much identical thing, so I've just changed column names and repurposed my old macro to do this one. 😄

challenge_307_LiuZhang.yxwz

challenge_307_LiuZhang.yxzp

anabelvelazque

Hi! Here is my take

Weekly Challenge 307_AV.yxmc

Erin

Thanks to @TonyA , we relied heavily on your posted solution. Brilliant!

Weekly Challenge 307_submission_EM.yxzp

binu_acs

solution attached

Weekly Challenge 307_Solution_BV.yxwz

kelly_gilbert

I decided to start this one fresh, without looking back at my solution to challenge #247 - Pairing Partners. (where I used Schurig tables). This time, I implemented the algorithm of rotating the teams around one fixed team.