Is it really time?

Question

A time in the format hhMMss is represented by six numbers in the range 0..9 (e.g.100203 for 3 seconds after 2 minutes after 10am (10:02.03), or 155603 for three seconds after 56 minutes after 3pm (15:56.03).

Treating these times as integers, these numbers are therefore in the range 000000 to 235959; but not all numbers in that range are valid times.

Normally, though, integers aren't represented with leading 0s, right?

So, this challenge is to take a numeric input (without leading 0s), and say whether it represents a proper time or not when the leading 0s are put back.

Input

Any integer, as a string or an integer type, in the range 0..235959 inclusive. all numbers as strings will be input with no leading 0s (e.g. 2400, not 002400). The time 000000 maps to 0; or exceptionally as . Inputs outside of this range should return Falsy, but there is no requirement that they are supported.

Output

Truthy/Falsy value - by which I mean there must be a consistent distinction in the output between True and False - e.g. True could be output as 1 and False could be any other output (or even a variable output) - as long as it can be documented how to tell what is True and what is not.

More Challenge Details

Given the input integer, figure out if the number represents a time (truthy) or not (falsy).

A number represents a time if a time (hhMMss) with leading 0s removed is the same as the number.

e.g. 00:00.24 is represented by 24
e.g. 00:06.51 is represented by 651 e.g. 00:16.06 is represented by 1606
e.g. 05:24.00 is represented by 52400
e.g. 17:25.33 is represented by 172533

There are therefore some numbers that can't represent times:

e.g. 7520 - this can't represent hhMMss because 00:75:20 isn't a time

As a general rule, the valid numbers fall into the pattern:

trimLeadingZeros([00..23][00..59][00..59]);

The following numbers are the entire set of inputs and the required answers for this challenge

seconds only (e.g. 00:00.ss, with punctuation and leading 0s removed, -> ss)
0 to 59 - Truthy
60 to 99 - Falsy

minutes and seconds (e.g. 00:MM.ss, with punctuation and leading zeros removed, -> MMss)
100 to 159 - Truthy
160 to 199 - Falsy
etc, up to:
2300 to 2359 - Truthy
2360 to 2399 - Falsy
2400 to 2459 - Truthy
2460 to 2499 - Falsy
etc, up to:
5900 to 5959 - Truthy
5960 to 9999 - Falsy

hours 0..9, minutes and seconds (e.g. 0h:MM.ss with punctuation and leading zeros removed -> hMMss)

10000 to 10059 - Truthy
10060 to 10099 - Falsy
etc, up to:
15800 to 15859 - Truthy
15860 to 15899 - Falsy
15900 to 15959 - Truthy
15960 to 19999 - Falsy

20000 to 20059 - Truthy
20060 to 20099 - Falsy
20100 to 20159 - Truthy
20160 to 20199 - Falsy
etc, up to:
25800 to 25859 - Truthy
25860 to 25899 - Falsy
25900 to 25959 - Truthy
25960 to 25999 - Falsy
etc, up to:
95800 to 95859 - Truthy
95860 to 95899 - Falsy
95900 to 95959 - Truthy
95960 to 99999 - Falsy

hours 10..23, minutes and seconds (e.g. hh:MM.ss with punctuation and leading zeros removed -> hhMMss)

100000 to 100059 - Truthy
100060 to 100099 - Falsy
100100 to 100159 - Truthy
100160 to 100199 - Falsy
etc, up to:
105800 to 105859 - Truthy
105860 to 105899 - Falsy
105900 to 105959 - Truthy
105960 to 109999 - Falsy

This pattern is then repeated up to:

235900 to 235959 - Truthy
(236000 onwards - Falsy, if supported by program)

leading 0s must be truncated in the input, if strings are used.

Code golf, so least bytes wins - usual rules apply

code-golf

Answer 1

Python, 45 43 38 27 bytes

For inputs up until 239999:

lambda n:n/100%100<60>n%100

You can try it online! Thanks @Jitse and @Scurpulose for saving me several bytes ;)

For inputs above 239999 go with 36 bytes:

lambda n:n/100%100<60>n%100<60>n/4e3

Answer 2

Perl 6, 33 25 bytes

-7 bytes thanks to Kevin Cruijssen

60>*.polymod(100,100).max

Try it online!

Answer 3

APL (Dyalog Extended), 19 bytes^SBCS

-10 bytes thanks to Kevin Cruijssen.

Anonymous tacit prefix function. Takes argument as integer.

⍱59<100∘⊤

Try it online!

100∘⊤ convert To base-100

59< are they, each, greater than 59?

⍱ are none of them true?

Answer 4

05AB1E, 14 13 12 bytes, supports inputs > 235959

твR₅0šR12*‹P

Try it online!

тв             # convert input to base 100
  R            # reverse
   ₅           # 255
    0š         # convert to list and prepend 0: [0, 2, 5, 5]
      R        # reverse: [5, 5, 2, 0]
       12*     # times 12: [60, 60, 24, 0]
          ‹    # a < b (vectorizes
           P   # product

Answer 5

Python, 35 bytes

f=lambda n:n<1or(n%100<60)*f(n/100)

A recursive function which returns 1 or True (which are truthy) if valid or 0 (which is falsey) if not.

Try it online! *

How?

True and False are equivalent to 1 and 0 respectively in Python.

The function (f=lambda n:...) checks that the last up-to-two digits as an integer (n%100) are less than sixty (<60), chops them off (n/100) and multiplies by a recursive call *f(...) until an input of zero is reached (n<1or) at which point True is returned. If at any stage the check fails a False is placed in the multiplication, which will then evaluate to 0 (a falsey value).

---

* Only f(0) evaluates to True, but set((True, 1, 1, ..., 1)) evaluates to {True} due to the equivalence of True and 1 in Python.

Answer 6

J, ^{32 26 23} 16 bytes

60*/ .>100#.inv]

Try it online!

-16 bytes (!!) thanks to Adam. This new solution uses the approach from his APL answer so be sure to upvote that.

Convert the input to base 100, check that all digits are less than 60.

Note the most significant digit is guaranteed to be less than 24 by the allowed inputs.

Answer 7

Perl 5 -p, 27 22 bytes

$_=!/[6-9].(?=(..)*$)/

Try it online!

Since the input is guaranteed to be less than 236000, the hours can be ignored as they will always be valid. This pattern match checks if there is a 6, 7, 8, or 9 in the tens digit of the minutes or seconds. The match is then negated to get truthy for valid dates and falsy for invalid ones.

Answer 8

Java 8, 38 bytes

n->n%100<60&n%1e4<6e3&n%1e6<24e4&n<1e6

Try it online!

Basically an improvement of @Kevin Cruijssen's solution; I don't have enough reputation for a comment.

Answer 9

Red, 63 bytes

f: func[n][either n % 100 > 59[return 0][if n > 1[f n / 100]]1]

Try it online!

Of course the recursive function with integers is much shorter than the below version that works on strings.

Red, 139 130 115 bytes

func[s][s: pad/left/with s 6 #"0"
not any collect[foreach n collect[loop 3[keep to 1 take/part s 2]][keep n > 60]]]

Try it online!

Answer 10

Java 8, 45 43 bytes

n->n%100<60&n%1e4/100<60&n%1e6/1e4<24&n<1e6

Improved by @Joja's Java answer by removing the divisions, so make sure to upvote him/her as well!

Try it online.

Explanation:

n->              // Method with integer parameter and boolean return-type
  n%100<60       //  Check whether the seconds are smaller than 60
  &n%1e4/100<60  //  and the minutes are smaller than 60
  &n%1e6/1e4<24  //  and the hours are smaller than 24
  &n<1e6         //  and the entire number is smaller than 1,000,000

Answer 11

Turing Machine Code, 336 548 bytes

Prints 't' for true and 'f' for false.

0 * * r !
! * * r "
! _ _ l b
b * _ l t
" * * r £
" _ _ l c
c * * l c
c _ _ r 4
£ * * r $
£ _ _ l d
d * * l d
d _ _ r 3
$ * * r ^
$ _ _ l e
e * * l e
e _ _ r 2
^ * * r &
^ _ _ l g
g * * l g
g _ _ r 1
& * * l &
& _ _ l O
O 1 1 r a
O 2 2 r 1
O * * * f
a * * r 2
1 0 0 r 2
1 1 1 r 2
1 2 2 r 2
1 3 3 r 2
1 * * * f
2 0 0 r 3
2 1 1 r 3
2 2 2 r 3
2 3 3 r 3
2 4 4 r 3
2 5 5 r 3
2 * * * f
3 * * r 4
4 0 0 r t
4 1 1 r t
4 2 2 r t
4 3 3 r t
4 4 4 r t
4 5 5 r t
4 * * * f
f * * l f
f _ _ r n
n * _ r n
n _ f * halt
t * * l t
t _ _ r y
y * _ r y
y _ t r halt

Try it online!

Added a chunk of bytes thanks to @Laikoni for spotting my misread of the question.

Answer 12

Jelly, 13 7 bytes

bȷ2<60Ạ

Try it online!

A monadic link taking an integer and returning 1 for true and 0 for false.

Thanks to @KevinCruijsen for saving 6 bytes!

Answer 13

LibreOffice Calc, 43 bytes

=MAX(MOD(A1,100),MOD(A1/100,100),A1/4e3)<60

Basically a blatant rip-off respectful port of @RGS excellent Python answer so go and upvote them. Only posted as I have not seen a LibreOffice Calc answer on here before and I was messing about while calculating my tax return this evening (code golf is much more fun). Screenshot of some test cases below.

Answer 14

x86-16, IBM PC DOS, 46  44  39 bytes

00000000: d1ee 8a0c ba30 4c88 5401 03f1 4ed1 e9fd  .....0L.T...N...
00000010: b303 ad86 e0d5 0a4b 7502 b628 3ac6 7d02  .......Ku..(:.}.
00000020: e2f0 d6b4 4ccd 21                        ....L.!

Build and test ISTIME.COM with xxd -r.

Unassembled listing:

D1 EE       SHR  SI, 1              ; SI = 80H
8A 0C       MOV  CL, BYTE PTR[SI]   ; CX = input length
BA 4C30     MOV  DX, 4C30H          ; DH = 60+16, DL = '0'
88 54 01    MOV  BYTE PTR[SI+1], DL ; 'zero' pad byte to the left of input
03 F1       ADD  SI, CX             ; SI to end of input string
4E          DEC  SI                 ; remove leading space from length
D1 E9       SHR  CX, 1              ; CX = CX / 2
FD          STD                     ; read direction downward
B3 03       MOV  BL, 3              ; counter to test if third iteration (meaning hours)
        LOD_LOOP:
AD          LODSW                   ; AX = [SI], SI = SI - 2
86 E0       XCHG AH, AL             ; endian convert
D5 0A       AAD                     ; binary convert
4B          DEC  BX                 ; decrement count
75 02       JNZ  COMP               ; if not third time through, go compare
B6 28       MOV  DH, 40             ; if third, set test to 24+16
        COMP:
3A C6       CMP  AL, DH             ; is number less than DL?
7D 02       JGE  NOT_VALID          ; if not, it's invalid
E2 F0       LOOP LOD_LOOP           ; otherwise keep looping
        NOT_VALID: 
D6          SALC                    ; Set AL on Carry
B4 4C       MOV  AH, 4CH            ; return to DOS with errorlevel in AL
CD 21       INT  21H                ; call DOS API

A standalone PC DOS executable. Input via command line, output DOS exit code (errorlevel) 255 if Truthy 0 if Falsy.

I/O:

Truthy:

Falsy:

Thanks to @PeterCordes for:

• -2 bytes use DOS exit code for Truthy/Falsy result
• -3 bytes eliminate ASCII conversion before AAD

Answer 15

Charcoal, 11 bytes

‹⌈⍘Ｎ⭆¹⁰⁰℅ι<

Try it online! Link is to verbose version of code. Accepts input from 0 to 239999 and outputs a Charcoal boolean, - for times, no output for non-times. Explanation:

     ¹⁰⁰    Literal 100
    ⭆       Map over implicit range and join
         ι  Current index
        ℅   Unicode character with that ordinal
   Ｎ        Input as a number
  ⍘         Convert to string using string as base
 ⌈          Character with highest ordinal
‹           Is less than
          < Character with ordinal 60
            Implicitly print

BaseString always returns 0 for a value of 0 (bug?) but fortunately this is still less than <.

Alternative solution, also 11 bytes:

⌈⍘Ｎ⭆¹⁰⁰›ι⁵⁹

Try it online! Link is to verbose version of code. Link is to verbose version of code. Accepts input from 0 to 239999 and outputs 0 for times, 1 for non-times. Explanation:

    ¹⁰⁰     Literal 100
   ⭆        Map over implicit range and join
        ι   Current index
       ›    Greater than
         ⁵⁹ Literal 59
  Ｎ         Input as a number
 ⍘          Convert to a string using string as base
⌈           Maximum
            Implicitly print

BaseString doesn't require the string base to have distinct characters, so this string just has 60 0s and 40 1s.

Unfortunately taking the base numerically returns an empty list for an input of zero, which takes an extra three bytes to handle, pushing the byte count above 11. But fortunately I can substitute an acceptable non-zero number in only two bytes, so another 11-byte alternative is possible:

›⁶⁰⌈↨∨Ｎχ¹⁰⁰

Try it online! Link is to verbose version of code. Accepts input from 0 to 239999 and outputs a Charcoal boolean, - for times, no output for non-times. Explanation:

 ⁶⁰         Literal 60
›           Is greater than
      Ｎ     Input as a number
     ∨      Logical Or
       χ    Predefined variable `10`
    ↨   ¹⁰⁰ Convert to base 100 as a list
   ⌈        Maximum
            Implicitly print

Answer 16

MathGolf, 18 9 bytes

◄+░2/i╙╟<

Try it online.

Explanation:

◄+        # Add builtin 10,000,000 to the (implicit) input-integer
  ░       # Convert it to a string
   2/     # Split it into parts of size 2: [10,hh,mm,ss]
     i    # Convert each to an integer
      ╙   # Pop and push the maximum
       ╟< # And check if it's smaller than builtin 60
          # (after which the entire stack joined together is output implicitly)

Answer 17

JavaScript (V8), 34 bytes

a=>a.match(/\d\d/g).every(x=>x<60)

Try it online!

Answer 18

K (ngn/k), 14 bytes

{0=+/59<100\x}

Try it online!

Based on Adám's APL solution and Kevin Cruijssen's suggestion.

Answer 19

Japt, 7 bytes

ìL e<60

Try it

Answer 20

Bash, 33 32 bytes

p=%100\<60;echo $[$1$p&$1/100$p]

Try it online!

Input is passed as an argument.

Output is 0 (falsey) or 1 (truthy).

(I've deleted an earlier 45-byte version that used egrep.]

Answer 21

Retina 0.8.2, 12 bytes

[6-9].(..)?$

Try it online! Link includes test cases. Accepts input from 0 to 239999 and outputs 0 for times, 1 for non-times. Explanation: Simply checks whether the second or fourth last digit is greater than 5.

Answer 22

Zsh, 28 bytes

e=%100/60;(($1$e||$1/100$e))

Try it online!

Returns via exit code.

Since $parameters are expanded before ((arithmetic)), $e expands to %100/60 before arithmetic is done.

There are 2 other 28 byte solutions I found as well, albeit not as interesting:

((h=100,$1%h/60||$1/h%h/60))

(($1%100/60||$1/100%100/60))

Answer 23

W, 6 bytes

Source compression ftw!

♀♥@p▒ö

Uncompressed:

2,a60<A

Explanation

2,      % Split number into chunks of length 2
        % The splitting is right-to-left *instead* of left-to-right.
      A % Is all items in the list ...
  a60<  % ... less than 60?

Answer 24

T-SQL, 42 bytes

Supports all positive integer input

Returns 1 for true, 0 for false

DECLARE @ INT=235959

PRINT-1/~(@/5000/48+@/100%100/60+@%100/60)

I was able to golf it 1 byte

@/10000/24 was changed to @/5000/48

Answer 25

Turing Machine Simulator, 299 272 269 bytes

0 _ _ l 1
0 * * r 0
1 * _ l 2
* _ t * t
2 6 f * f
2 7 f * f
2 8 f * f
2 9 f * f
2 * _ l 3
3 * _ l 4
4 6 f * f
4 7 f * f
4 8 f * f
4 9 f * f
4 * _ l 5
5 0 _ l 6
5 1 _ l 6
5 2 _ l 6
5 3 _ l 6
5 * _ l 7
6 _ t * t
6 1 t * t
6 2 t * t
6 * f * f
7 _ * * t
7 1 _ * t
7 * f * f

Run in Turing Machine Simulator. Halts with t on the tape for true inputs and a prefix of the input and f for false inputs.

Answer 26

Wolfram Language (Mathematica), 76 bytes

supports any number

!FreeQ[FromDigits/@Join@@@IntegerDigits/@Tuples[Range/@{24,6,10,6,10}-1],#]&

Try it online!

Answer 27

Perl 5, 42 39 +1 (-p) = 40 bytes

$_=0|!($_%100>59|$_/1e4%10>5|$_/1e5>23)

Saved 3 bytes by changing to exponent notation (1000 => 1e4)

Try it online!

Answer 28

T-SQL, 64 bytes

SELECT*FROM t WHERE 60>LEFT(RIGHT('000'+v,4),2)AND 60>RIGHT(v,2)

Input is taken from pre-existing table t with varchar field v, per our input standards.

Outputs 1 row (with the original value) for "true", and 0 rows for "false".

Accepts only values in the specified range (0 to 235959), so doesn't validate the first 2 digits.

Answer 29

Python 3, 90 85 bytes

lambda t:{t}&s
s={0}
import time
while len(s)<86400:s|={int(time.strftime("%H%M%S"))}

Try it online!

The idea is to simply create a set of all valid time (as int), then check if the given number is in the set. The set is created by repeatedly adding the current time to the set until all 86400 distinct values are added. Returns: non-empty set if t is valid time, otherwise empty set.

Answer 30

JavaScript (ES6),  27 26  21 bytes

Takes input as an integer in hhmmss format. Returns \$0\$ or \$1\$.

n=>n%100<60&n%1e4<6e3

Try it online!

How?

n=>n%100<60&n%10000<6000

is just as long as:

n=>n%100<60&n/100%100<60

But from there we can use the scientific notation to save 3 bytes:

n%10000<6000
n%1e4<6e3

Answer 31

JavaScript (Babel Node), 71 52 bytes

t=i=>{[,,m,,s]=(i+'').padStart(6,0);return m<6&&s<6}

Try it online!

Answer 32

PHP, 60 bytes

<?=preg_match('#\d+([01]\d|2[0-3])([0-5]\d){2}#',$argn+1e6);

Try it online!

Basically regex and not much golfable, but fun. Inputs above 235959 are indeterminate.

Answer 33

Wolfram Language (Mathematica), 44 bytes

#&@@TimeObject[x=IntegerDigits[#,100,3]]==x&

Try it online!

Works for values above 235959!

The built-in TimeObject command can automatically round up each element!

Explanation

x=IntegerDigits[#,100,3]

Split input in base-100 (i.e. in chunks of 2 digits), padded to length 3. Store that list in x.

TimeObject[...]

Convert that to a TimeObject.

#&@@...

Extract the rounded string

...==x

Check if that is equal to x (i.e. nothing rounded up).

The boring version, 28 bytes

Max@IntegerDigits[#,100]<60&

Try it online!

Answer 34

C (gcc), 30 bytes

f(n){n=n%100<60&n/100%100<60;}

Doesn't check hours.

Try it online!

C (gcc), 39 bytes

f(n){n=n%100<60&n/100%100<60&n/1e4<24;}

Checks hours.

Try it online!

Answer 35

MUMPS, 74 70 64 40 bytes

t(t) s l=$l(t)-5 f f=l:2:7 q:$e(t,f,f+1)>$s(f-l:59,1:23)
 q f>5

Ah, I didn't consider that you only need to handle values up to 239999. That drops it from 64 to 40.

t(t) f f=$l(t)-3:2:7 q:$e(t,f)>5
 q f>5

Answer 36

Jelly, 7 bytes

ṚHÐoṀ<6

Try it online!

How?

ṚHÐoṀ<6 - Link: integer, n                 e.g.  236059
Ṛ       - (implicit digits of n) reversed        [9  , 5  , 0  , 6  , 3  , 2  ]
  Ðo    - apply to odd indices:
 H      -   halve                                [4.5, 5  , 0  , 6  , 1.5, 2  ]
    Ṁ   - maximum                                6
      6 - six                                    6
     <  - less than?                             0

---

Alternative 7:

ṚḊm2Ṁ<6 - reverse, dequeue, modulo-2-slice, maximum, less than 6?

Answer 37

JavaScript (Node.js), 49 bytes

t=> !!(t+'').padStart(6,0).match(/..([0-5]\d){2}/)

Simple Javascript Regular Expression

Try it online!

Answer 38

VBA, 149 bytes

x=1: i=""
If Len(i)<6 Then Do Until Len(i)=6: i="0"&i: Loop
s = Right(i, 2): m = Left(Right(i,4),2): h = Left(i,2)
If s>59 Or m>59 Or h>23 Then x=0

Works for values above 235959, assigns x to output 1 or 0 with input as i