Irish Snap: Variant Rules0 s Bolan250Jjns G14:i00_t ediEeSpMa31.
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
10 Answers
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.
05AB1E, 7 bytes
α12%ß2‹
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Takes inputs as [middle, bottom], top.
α # absolute difference
12% # mod 12
ß # minimum
2‹ # less than 2?
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
-
\\$\\begingroup\\$ Too bad whitespace is required before
<, this was the perfect chance to have a heart smiley. \\$\\endgroup\\$ – Grimy 8 hours ago
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 5The numbers 3 and 5 in binary are0 1 1and1 0 1which 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?
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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-
\\$\\begingroup\\$
%144could be%72\\$\\endgroup\\$ – Grimy 8 hours ago -
\\$\\begingroup\\$ @Grimy Thanks! FWIW,
%13would also work. \\$\\endgroup\\$ – Arnauld 8 hours ago
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
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
Jelly, 6 bytes
ạ%12ṠƑ
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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
C (gcc), 47 43 bytes
f(b,m,t){return(1<<t-m|1<<t-b)&0x80101003;}
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top, [middle, bottom]? \\$\\endgroup\\$ – Jo King 9 hours ago