Irish Snap: Variant Rules

Question

Introduction

Recently, me and a couple of my friends decided to play some cards, and one of them suggested the game 'Irish Snap', which was the inspiration for this challenge. However, I later learnt that the game has a lot of different rules that you can play with, some of which are listed here. The rules that are in this challenge aren't currently listed on that page, hence the name, 'Variant Rules'

The Challenge

Given an array of 3 cards, output a truthy or falsey value depending on if they make a valid snap in a game of Irish snap.

Input

The input will be an array of 3 numbers, ranging from 1-13 inclusive, with 1 representing an ace, 11 representing a jack, 12 representing a queen and 13 representing a king. The input can be in any order of top, middle, bottom.

Rules

The 4 different criteria for if cards make an Irish snap are:

The top and middle cards are the same
The top and middle cards have a difference of one
The top and bottom cards are the same
The top and bottom cards have a difference of one

If any of these criteria are met, you must output a truthy value. As well as this, for the two criteria that require the cards to have a difference of one, it 'wraps around', meaning that an ace and a king are considered to have a difference of one, and vice versa.

Test Cases

Input (Bottom, Middle, Top) -> Output
1 13 7 -> False
1 4 13 -> True
9 3 6 -> False
8 9 7 -> True
2 6 5 -> True
12 5 11 -> True
10 4 8 -> False
12 13 7 -> False
9 7 10 -> True
7 3 1 -> False
4 2 3 -> True

Can we take the cards seperately? Or take input as top, [middle, bottom]? — Jo King, Aug 22 at 12:52
Can we invert the output, i.e return False for valid snaps and vice versa? How about a test case where both middle and bottom are valid? — Jo King, Aug 22 at 13:11
Must the output values be consistent or could we, for example, output 0 for false and any other integer for true or, even, any negative integer for false or any positive integer for true? — Shaggy, Aug 22 at 23:11

Arfie · Accepted Answer · 2019-08-22 13:10:23Z

4

Python 3, 38 bytes

lambda x,y,z:{x-y,x-z}&{0,1,12,-1,-12}

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Returns a non-empty set (truthy) if valid, empty set (falsey) if not. Takes input in order top-middle-bottom, but can be rearranged for same code size.

answered Aug 22 at 13:10

Arfie

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Jo King · Accepted Answer · 2019-08-22 13:14:46Z

4

Perl 6, 16 bytes

3>(*-(*|*)+1)%13

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Anonymous whatever lambda that takes input as top, middle, bottom and returns a Junction that evaluates to True or False

edited Aug 22 at 13:14

answered Aug 22 at 13:00

Jo King

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\$\begingroup\$ Too bad whitespace is required before <, this was the perfect chance to have a heart smiley. \$\endgroup\$ – Grimy Aug 22 at 13:18

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Grimy · Accepted Answer · 2019-09-23 09:04:42Z

3

05AB1E, 7 6 bytes

α12%ß!

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Takes inputs as [middle, bottom], top.

α        # absolute difference
 12%     # mod 12
    ß    # minimum
     !   # factorial

Only 1 is truthy in 05AB1E. 0! and 1! are both 1, while no other number has a factorial of 1.

edited Sep 23 at 9:04

answered Aug 22 at 12:56

Grimy

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Jonah · Accepted Answer · 2019-08-22 13:10:01Z

J, 12 bytes

1 e.2>12||@-

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Taking bottom middle as left arg, top as right arg.

original answer taking input as one list

J, 24 bytes

1 e.2>#:@3 5(12||@-/)@#]

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#:@3 5 The numbers 3 and 5 in binary are 0 1 1 and 1 0 1 which are the masks for the middle/top and bottom/top cards respectively
(12||@-/)@# We filter the input with those masks, take the abs value of the resulting differences, then the remainder when divided by 12 (for the ace-king case)
1 e.2> are either of the resulting numbers less than 2, ie, 0 or 1?

Arnauld · Accepted Answer · 2019-08-22 13:54:11Z

2

JavaScript (ES6), 29 bytes

Takes input as ([bottom, middle])(top).

The output is inverted.

a=>c=>a.every(n=>(n-c)/2%6|0)

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JavaScript (ES6), 37 30 bytes

Saved 1 byte thanks to @Grimy

Takes input as ([bottom, middle])(top).

a=>c=>a.some(n=>(n-=c)*n%72<2)

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edited Aug 22 at 13:54

answered Aug 22 at 13:05

Arnauld

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\$\begingroup\$ %144 could be %72 \$\endgroup\$ – Grimy Aug 22 at 13:08
\$\begingroup\$ @Grimy Thanks! FWIW, %13 would also work. \$\endgroup\$ – Arnauld Aug 22 at 13:34

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Neil · Accepted Answer · 2019-08-22 20:41:49Z

Charcoal, 12 bytes

›²⌊﹪↔⁻Ｅ²ＮＮ¹²

Try it online! Port of @Grimy's answer. Takes input as three separate values bottom, middle, top, and outputs using Charcoal's default Boolean format of - for true, nothing for false. Explanation:

 ²              Literal 2
›               Is greater than
  ⌊             Minimum of
    ↔            Absolute value of (vectorised)
      Ｅ²Ｎ       First two numeric inputs as a list ([bottom, middle])
     ⁻          Minus (vectorised)
         Ｎ      Third input (top)
   ﹪            Modulo (vectorised)
          ¹²    Literal 12

Xcali · Accepted Answer · 2019-08-22 16:23:14Z

1

Perl 5 `-ap`, 31 bytes

$t=<>}{$\|=abs($t-$_)%12<2for@F

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Input:

bottom middle
top

Actually, the order of the middle and bottom doesn't matter.

Output:

0 for false; 1 for true

answered Aug 22 at 16:23

Xcali

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ar4093 · Accepted Answer · 2019-08-22 16:35:39Z

Pyth, 12 11 bytes

Takes input as [bottom, top, middle] or [middle, top, bottom] (both work). Outputs [] (Falsy in Pyth) if there's no valid snap, a non-empty array otherwise.

f>2%.aT12.+

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If a consistent truthy/falsy value is required, add .A in front for +2 bytes. Then output will be True or False.

Explanation

  f             # Filter on lambda T:
   >2           # 2 > 
      .aT       #     abs(T)
     %   12     #            % 12
           .+   # the list of deltas (difference between consecutive elements)

.A (if required)# Any truthy values in the above list?

Edit: -1 with a different approach

Erik the Outgolfer · Accepted Answer · 2019-08-22 17:38:57Z

1

Jelly, 6 bytes

ạ%12ṠƑ

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answered Aug 22 at 17:38

Erik the Outgolfer

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G. Sliepen · Accepted Answer · 2019-08-22 18:23:54Z

1

C (gcc), 47 43 bytes

f(b,m,t){return(1<<t-m|1<<t-b)&0x80101003;}

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edited Aug 22 at 18:23

answered Aug 22 at 18:15

G. Sliepen

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Embodiment of Ignorance · Accepted Answer · 2019-08-23 02:57:09Z

1

Japt, 7 bytes

d_aV <2

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answered Aug 23 at 2:57

Embodiment of Ignorance

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Nick Kennedy · Accepted Answer · 2019-08-23 13:48:15Z

1

Jelly, 6 bytes

I%12ỊẸ

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A monadic link taking the list of [middle, top, bottom] as its argument and returning 1 for snap and 0 for no snap.

answered Aug 23 at 13:48

Nick Kennedy

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t-clausen.dk · Accepted Answer · 2019-08-24 14:00:08Z

1

T-SQL 2008, 40 bytes

PRINT 1/-~abs((@-@2)%12/2*((@-@3)%12/2))

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edited Aug 24 at 14:00

answered Aug 23 at 11:45

t-clausen.dk

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Zahiro Mor · Accepted Answer · 2019-09-23 11:30:39Z

0

[R], 23 bytes

takes input as a=c(bottom,top,middle):

any(abs(diff(a))%%12<2)

answered Sep 23 at 11:30

Zahiro Mor

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Irish Snap: Variant Rules

Introduction

The Challenge

Input

Rules

Test Cases

14 Answers 14

Python 3, 38 bytes

Perl 6, 16 bytes

05AB1E, 7 6 bytes

J, 12 bytes

original answer taking input as one list

J, 24 bytes

JavaScript (ES6), 29 bytes

JavaScript (ES6), 37 30 bytes

Charcoal, 12 bytes

Perl 5 `-ap`, 31 bytes

Input:

Output:

Pyth, 12 11 bytes

Explanation

Jelly, 6 bytes

C (gcc), 47 43 bytes

Japt, 7 bytes

Jelly, 6 bytes

T-SQL 2008, 40 bytes

[R], 23 bytes

Your Answer

Not the answer you're looking for? Browse other questions tagged code-golf decision-problem card-games cards or ask your own question.

Hot Network Questions

Irish Snap: Variant Rules

Introduction

The Challenge

Input

Rules

Test Cases

14 Answers 14

Python 3, 38 bytes

Perl 6, 16 bytes

05AB1E, 7 6 bytes

J, 12 bytes

original answer taking input as one list

J, 24 bytes

JavaScript (ES6), 29 bytes

JavaScript (ES6), 37 30 bytes

Charcoal, 12 bytes

Perl 5 -ap, 31 bytes

Input:

Output:

Pyth, 12 11 bytes

Explanation

Jelly, 6 bytes

C (gcc), 47 43 bytes

Japt, 7 bytes

Jelly, 6 bytes

T-SQL 2008, 40 bytes

[R], 23 bytes

Your Answer

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Not the answer you're looking for? Browse other questions tagged code-golf decision-problem card-games cards or ask your own question.

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Perl 5 `-ap`, 31 bytes