Problem 42839. Identify the sequence

Created by HH

Solve Later

Given a row vector, x, return 1 if it is an arithmetic series, or 2 if it is a geometric series. If it is neither, return 0.

Example 1:

x = 1:8

y = 1

Example 2:

x = 2^(1:8)

y = 2

Example 3:

x = [1 1 2 3 5 8 13 21 34]

y = 0

Solve

Solution Stats

Last solution submitted on Aug 29, 2018

Last 200 Solutions

Problem Comments

5 Comments

5 Comments

Show 2 older comments

Peng Liu on 2 May 2016

Perhaps a better strategy is to make a new problem instead of frequently re-scoring due to incremental changes. BTW, the newly added last test case (#11) should return 2, not 1.

Jean-Marie Sainthillier on 2 May 2016

Yes, Test 11 -> 2

Tim on 5 May 2016

Test case 11 is still incorrect.

Jean-Marie Sainthillier on 9 May 2016

x = [i -2 -4i 8 16i] is an arithmetic serie ?

HH on 27 May 2016

Test case 11 fixed. Thanks.

Solution Comments

Solution 884844

1 Comment

1 Comment

Jan Orwat on 2 May 2016

Your "if ..." returns false positive on complex input.

Solution 883780

2 Comments

2 Comments

Peng Liu on 28 Apr 2016

This solution will fail a test with x = [1 1 -1 -1]; y_correct = 0; assert(isequal(stype(x),y_correct)); Thus, I recommend to reinforce the test suite by adding this test.

HH on 30 Apr 2016

Indeed. Test added. Thanks!

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Problem Tags

sequences