As Easy as One-Two-Three

Question

Write a program or function that takes in a positive integer. You can assume the input is valid and may take it as a string. If the number is any of

then output a truthy value. Otherwise, output a falsy value. For example, the inputs

must all result in falsy output. (The input will not have leading zeroes so you needn't worry about things like 012.)

The shortest code in bytes wins.

@Lynn No. 012 would be falsy but you can assume it is not input. — Calvin's Hobbies, Commented Aug 30, 2016 at 4:45
@BradGilbertb2gills No. It should just satisfy the linked definition of truthy/falsy - meta.codegolf.stackexchange.com/questions/2190/… — Calvin's Hobbies, Commented Aug 30, 2016 at 4:46

DLosc · Accepted Answer · 2024-04-09 05:08:54Z

1

Pip, 8 bytes

^a=@a+,3

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Explanation

^a=@a+,3
^a       ; Split argument into list of digits
  =      ; That list numerically equals
      ,3 ; Range(3)
   @a+   ; plus first digit of argument

answered Apr 9 at 5:08

DLosc

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

Excel - 104 bytes

=IF(LEN(N)<3,"Falsy",IF(AND(LEN(N)=3,MID(N,2,1)-MID(N,1,1)=1,MID(N,3,1)-MID(N,2,1)=1),"Truthy","Falsy"))

Explanation:

The syntax for the IF formula in Excel is:

IF( condition, [value_if_true], [value_if_false] )

If the length of input N, where it's a name of the reference cell, is less than 3, then it will return Falsy. Else, if the length of input N is 3 and both of the difference of second digit and first digit and the difference of third digit and second digit are equal to 1, then it will return Truthy.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Aug 30, 2016 at 4:04

Anastasiya-Romanova 秀

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\$\begingroup\$ 21 bytes: =REPT(LEFT(N),3)+12=N where N is the name of the reference cell. \$\endgroup\$
– Engineer Toast
Commented May 8, 2017 at 18:24

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

PHP, 35 bytes

<?=($n=$argv[1]-99)<790&$n%111==24;

exploiting that the modulo of a negative number is never positive in PHP

edited Jun 17, 2020 at 9:04

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answered Aug 30, 2016 at 8:09

Titus

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cleblanc · Accepted Answer · 2016-08-30 16:46:11Z

0

C 61 Bytes

f(char*v){puts(v[3]==0&v[0]+1==v[1]&v[1]+1==v[2]?"T":"F");}
g(v){puts(v<790&v%111==12?"T":"F");}
main(c, v)char**v;{
    f(v[1]);
    g(atoi(v[1]));
}

61 Bytes only includes the function. f(...) 36 Bytes using the trick from Geobits in g(...)

answered Aug 30, 2016 at 16:46

cleblanc

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mathreadler · Accepted Answer · 2016-08-30 17:15:57Z

GNU Octave : 74 bytes

golfed:

function r=g(a)t=conv(a-'0',[1,-1],'valid')==1;r=(sum(t)==2).*prod(t);end;

ungolfed:

function r=golf_123(a)
  t=conv(a-'0',[1,-1],'valid')==1;
  r=(sum(t)==2).*prod(t);
endfunction

Explanation: Treat the string as an integer vector, any two consecutive digits will then have derivative given the finite difference filter [1,-1] equal to 1 at each valid convolution output. The prod command calculates product, so it will short circuit to 0 if at least one entry is 0. The sum(t)==2 disqualifies any run of increasing digits longer or shorter than 3.

Numberknot · Accepted Answer · 2016-08-30 20:00:38Z

0

JAVA 7, 57 bytes

boolean f(int x){return (int)Math.log(x)-1==3&x%111==12;}

answered Aug 30, 2016 at 20:00

Numberknot

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\$\begingroup\$ You can remove the space in return (int) \$\endgroup\$
– Cyoce
Commented Dec 5, 2016 at 15:45

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Brian · Accepted Answer · 2016-08-30 21:06:47Z

0

SpecBAS - 35 bytes

1 INPUT n: ?(n-12)/111 in [1 TO 7]

Uses the same formula as the Powershell answer, returns 0 for False and 1 for True.

My original version was 59 bytes (and seems more "honest" for being my own work). Input as number and converted to string to avoid "012" showing as True.

1 INPUT n: n$=STR$ n: ?LEN n$=3 AND POS(n$,"0123456789")>0

answered Aug 30, 2016 at 21:06

Brian

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Lorentz Vedeler · Accepted Answer · 2016-08-31 11:10:10Z

0

C# 6 (36 bytes)

bool f(int x)=>x<790&0==(x+321)%111;

answered Aug 31, 2016 at 11:10

Lorentz Vedeler

1012 bronze badges

\$\begingroup\$ Is f necessary? \$\endgroup\$
– Cyoce
Commented Dec 4, 2016 at 0:22

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Stefano Sanfilippo · Accepted Answer · 2016-09-01 09:25:59Z

C, 71 bytes

Taking the input as int:

f,d,c;F(n){for(f=c=0;n;)d=n%10,c++,f|=d-(n/=10)%10-1&&n;return!f&c==3;}

Test main:

int main() {
  printf("%d\n", F(123));
  printf("%d\n", F(234));
  printf("%d\n", F(345));
  printf("%d\n", F(456));
  printf("%d\n", F(567));
  printf("%d\n", F(678));
  printf("%d\n", F(789));
  printf("%d\n", F(1));
  printf("%d\n", F(2));
  printf("%d\n", F(3));
  printf("%d\n", F(12));
  printf("%d\n", F(122));
  printf("%d\n", F(124));
  printf("%d\n", F(321));
  printf("%d\n", F(457));
  printf("%d\n", F(777));
  printf("%d\n", F(890));
  printf("%d\n", F(900));
  printf("%d\n", F(1011));
  printf("%d\n", F(1230));
  printf("%d\n", F(1234));
}

Blue · Accepted Answer · 2016-09-01 12:45:53Z

0

Ruby, 114 bytes

i = gets.chomp.to_i
l = [123, 234, 345, 456, 567, 678, 789]
y=false
l.each {|x| if i==x then y=true end;}
puts y

I don't know how many bytes this answer is, but I'm guessing it's not that small.

edited Sep 1, 2016 at 12:45

Blue

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answered Sep 1, 2016 at 12:27

user59211

1

\$\begingroup\$ Do you need those spaces? \$\endgroup\$
– Blue
Commented Sep 1, 2016 at 12:46
1

\$\begingroup\$ You can remove all but one space (puts y)..each can be .map. false can be p. if i==x then y=true end; can be i==x&&y=1 \$\endgroup\$
– Cyoce
Commented Dec 4, 2016 at 0:09

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ntalbs · Accepted Answer · 2016-09-02 12:07:42Z

0

Clojure, 48 bytes

(defn f [n] (= n ((set (range 123 900 111)) n)))

Test:

user=> (map (fn [n] [n (f n)]) [123 234 345 456 567 678 789])
([123 true]
 [234 true]
 [345 true]
 [456 true]
 [567 true]
 [678 true]
 [789 true])

user=> (map (fn [n] [n (f n)]) [1 2 3 12 122 124 132 321 457 777 890 900 1011 1230 1234])
([1 false]
 [2 false]
 [3 false]
 [12 false]
 [122 false]
 [124 false]
 [132 false]
 [321 false]
 [457 false]
 [777 false]
 [890 false]
 [900 false]
 [1011 false]
 [1230 false]
 [1234 false])

answered Sep 2, 2016 at 12:07

ntalbs

1316 bronze badges

\$\begingroup\$ I swear I didn't copy your answer! This can be significantly reduced. See my answer which is the same idea, but without all of the extra bits. \$\endgroup\$
– Carcigenicate
Commented Feb 14, 2017 at 20:43

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Samsquanch · Accepted Answer · 2016-09-02 16:26:22Z

0

PHP 5.6, 48 bytes

<?=($a=$argv[1])==join("",range($a[0],$a[0]+2));

Wanted to try something a little different from the other PHP answers (and a different approach to most of the posted answers). Take the first number of the input string, add two to it and create a range array, then join those together to create a new string and then return if they're equal or not.

Run with:

echo '<?=($a=$argv[1])==join("",range($a[0],$a[0]+2));' | php -- 123

answered Sep 2, 2016 at 16:26

Samsquanch

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Callum Kerr · Accepted Answer · 2016-09-02 19:51:41Z

0

><> (Fish), 28 Bytes

l3-0=?v0n;>
?+1-@:<;n1^?+2-!

Input is via an execution argument to add each digit to stack, left to right.

Checks if the length of the stack (number) is three, then that there's a difference of one between the third and second digits, then that there's a difference of two between the first and third digits.

Try it online!

answered Sep 2, 2016 at 19:51

Callum Kerr

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

Jelly, 8 bytes

Not as short as Dennis's answer (duh), but I'm quite proud of myself for getting the results I wanted out of Jelly.

9Rṡ3
De¢

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Explanation:

9R    Push 1-9 to the stack
ṡ3    Slice up the stack in parts of 3, overlapping
      This gives us [1,2,3], [2,3,4], ..., [7,8,9]
D     Convert input to list ( '123' -> [1, 2, 3])
e¢    This checks to see if the decimal list is in the list of our previous link.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Dec 3, 2016 at 10:55

steenbergh

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

Clojure, 25 bytes

(set (range 123 790 111))

Basically the Haskell answer. Creates a range which includes all the truthy answers, then converts it into a set. Sets are functions in Clojure (they implement the function interface and can be called).

Returns the number as the truthy return (every number is truthy in Clojure), and nil for the falsey value.

Use:

(let [s (set (range 123 790 111))]

    (s 123)
    123

    (s 234)
    234

    (s 993)
    nil

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Feb 14, 2017 at 20:40

Carcigenicate

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

SmileBASIC, 27 bytes

INPUT N?N-12==N DIV&H64*111

Using Dennis's algorithm.

If forcing the user to add &H to their input is OK, this works for 24 bytes:

INPUT N?N-18==(N>>8)*273

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Feb 14, 2017 at 21:07

12Me21

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

QBIC, 21 bytes

;[7|~!12+111*a$=A|_Xq

This prints 1 if a match is found, nothing otherwise.

Explanation

;              Get A$ from the command line
[7|            FOR a=1; a <=7 ; a++ (for each of the 7 sequences)
  12+111*a     Generate the number 123, 234, 345 by mult. 111 x index, plus 12
 !        $    Cast that to string B$
~          =A  And IF that matches A$
|_Xq           THEN quit, printing 1
               IF and FOR loop implicitly closed

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Feb 14, 2017 at 21:35

steenbergh

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Community · Accepted Answer · 2020-06-17 09:04:33Z

0

AWK, 33 28 27 Bytes

{$0=($1-12)/111~/^[1-7]$/}1

Prints 1 for corresponds to one of the desired values, 0 otherwise.

Updated answer is based on TimmyD's powershell answer.

Example usage:

awk '{$0=($1-12)/111~/^[1-7]$/}1' <<< 789

Prints 1

awk '{$0=($1-12)/111~/^[1-7]$/}1' <<< 12

Prints 0

Since this is using division rather than modulus, the result will be an integer for the desired values, but that integer needs to be between 1 and 7.

Try it online!

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Aug 30, 2016 at 20:25

Robert Benson

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\$\begingroup\$ 21 bytes. Echoes for truthy, ignores for falsey. \$\endgroup\$
– user100411
Commented Mar 30, 2021 at 9:11

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bwillsh · Accepted Answer · 2017-05-08 21:12:45Z

Befunge-93, 57 53 bytes

#@ #.0 &# ::57*2+3*%34*-#<_# 34*`!#<_# 98*34**`#<_1.@

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Explanation

#@ #.0        skip the terminator and output command. Adds a meaningless zero to 
                the stack.
&# ::         take in an input and add two more copies to the stack
57*2+3*%      adds input mod 111 ((5*7+2)*3) to the stack
34*-#<_#      compares 12 to the result, if they are the same, continue to move 
                right, else move left
34*`!#<_#     checks to see that the input is greater (`) than 12. If it is, 
                continue to move right, else move left
98*34**`#<_   check that 864 (9*8*3*4) is greater than the input. (the reason for 
                this is that 864 was an easy number to create that was greater than 
                the last possible number (789) and was less than the next number 
                divisible by 111 (900)
1.@           if you pass all the checks, output 1, otherwise...
@.0># &#      you will move back through the code heading left. (you will do 
                the operations, but that will not matter.) Skip the input 
                command. Output zero and end the code.

Community · Accepted Answer · 2020-06-17 09:04:33Z

0

Thue, 84 bytes

123z::=~1
234z::=~1
345z::=~1
456z::=~1
567z::=~1
678z::=~1
789z::=~1
a::=:::
::=
az

Outputs 1 when given one of the target values, and no output when given something else. The z at the end is needed to prevent false positives with numbers like 1230

edited Jun 17, 2020 at 9:04

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answered May 9, 2017 at 19:08

The Fifth Marshal

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The Thonnu · Accepted Answer · 2023-02-27 07:25:14Z

0

Thunno, \$ 8 \log_{256}(96)\approx \$ 6.58 bytes

dz[11dA=

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Port of Emigna's 05AB1E answer.

answered Feb 27, 2023 at 7:25

The Thonnu

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Stack Exchange Network

As Easy as One-Two-Three

81 Answers 81

Pip, 8 bytes

Explanation

Excel - 104 bytes

PHP, 35 bytes

GNU Octave : 74 bytes

JAVA 7, 57 bytes

SpecBAS - 35 bytes

C# 6 (36 bytes)

C, 71 bytes

Ruby, 114 bytes

Clojure, 48 bytes

PHP 5.6, 48 bytes

><> (Fish), 28 Bytes

Jelly, 8 bytes

Clojure, 25 bytes

SmileBASIC, 27 bytes

QBIC, 21 bytes

AWK, 33 28 27 Bytes

Befunge-93, 57 53 bytes

Thue, 84 bytes

Thunno, \$ 8 \log_{256}(96)\approx \$ 6.58 bytes

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As Easy as One-Two-Three

81 Answers 81

Pip, 8 bytes

Explanation

Excel - 104 bytes

PHP, 35 bytes

GNU Octave : 74 bytes

JAVA 7, 57 bytes

SpecBAS - 35 bytes

C# 6 (36 bytes)

C, 71 bytes

Ruby, 114 bytes

Clojure, 48 bytes

PHP 5.6, 48 bytes

><> (Fish), 28 Bytes

Jelly, 8 bytes

Clojure, 25 bytes

SmileBASIC, 27 bytes

QBIC, 21 bytes

AWK, 33 28 27 Bytes

Befunge-93, 57 53 bytes

Thue, 84 bytes

Thunno, \$ 8 \log_{256}(96)\approx \$ 6.58 bytes

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