Problem 661. Spot the outlier

Created by Ned Gulley

Solve Later

All points except for one lie on a line. Which one is the outlier?
Example:
You are given a list of x-y pairs in a column like this:
 pts = [ 0 1 
         0 2 
         3 2
         0 3 
         0 4 ]
You would return the number 3, since the third point is the only one that is non-collinear with the other points. All the others are on the y-axis.
 outlier = 3
 

Solve

Solution Stats

2534 Solutions
473 Solvers

Last Solution submitted on Jan 14, 2026

Last 200 Solutions

Problem Comments

3 Comments

3 Comments

Justin on 29 Apr 2014

The instructions were a bit confusing at first. It would have been better to say "Find the row number of the outlying point."

Also, using the third row as an answer and a 3 in a column of zeros makes it seem like the intent was to provide unclear instructions. (Or they are just used to writing college textbooks ;) )

Wenwu on 8 Jan 2015

The test set cases 2,3 seems to have two outliers for each case. Please check it

Josh on 10 Aug 2023

i struggled with this one, not so much because of the concepts/maths involved, but because of issues with floating point precision that occur with test case 3 where my functions kept erroring after determining that 15.0000 ~= 15

Solution Comments

Show comments

Problem Recent Solvers473

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 661. Spot the outlier

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers473

Suggested Problems

More from this Author54

Problem Tags

Community Treasure Hunt

Problem 661. Spot the outlier

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers473

Suggested Problems

More from this Author54

Problem Tags

Community Treasure Hunt

Players