Range, Reverse, Sum!

Question

Given a positive integer n as input, output the reversed range sum of n.

A reversed range sum is created by making an inclusive range up to n, starting with 1 and including n, reversing each of the numbers inside, and summing it.

Example:

Here is what would happen for an input of 10:

Range: [1,2,3,4,5,6,7,8,9,10]

Reverse: [1,2,3,4,5,6,7,8,9,01] (1-char numbers reversed are themselves, 10 reversed is 01 or 1)

Sum: 46

Numbers with 3+ digits are reversed the same way numbers with 2 digits are. For example, 1234 would become 4321.

Test cases:

Input -> Output

10 -> 46
5 -> 15
21 -> 519
58 -> 2350
75 -> 3147
999 -> 454545

Complete text cases to input of 999 can be found here, thanks very much to @fireflame241.

More test case results (not numbered, sorry, but you can parse through and get their line number if you want): Try it online! — Stephen, Jul 31, 2017 at 23:49
-1 because this is uninteresting. It seems like most, if not all, of the submissions are using the same approach. This challenge seems like a bunch of problems that have already been asked, just piped together with no obvious shortcuts. — Esolanging Fruit, Aug 21, 2017 at 8:23

notjagan · Accepted Answer · 2017-08-01 00:40:54Z

2

Pyth, 8 6 bytes

^{-2 bytes thanks to FryAmTheEggman!}

sms_`h

Try it online!

edited Aug 1, 2017 at 0:40

answered Jul 31, 2017 at 23:44

notjagan

4,2018 silver badges27 bronze badges

\$\begingroup\$ 1 byte longer version, sms_`dS, that does not abuse implicit U at the end. \$\endgroup\$
– Mr. Xcoder
Aug 1, 2017 at 6:44

Add a comment |

sergiol · Accepted Answer · 2017-08-01 08:13:20Z

2

Tcl, 66 bytes

time {incr s [regsub ^0+ [string rev $n] ""];incr n -1} $n
puts $s

Try it online!

answered Aug 1, 2017 at 8:13

sergiol

3,3981 gold badge14 silver badges31 bronze badges

Add a comment |

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

2

Neim, 4 bytes

Δ𝐫)𝐬

Try it online!

Explanation

Δ )              for each element 1 to n (outputs list)
 𝐫               reverse 
   𝐬             sum

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Aug 1, 2017 at 9:21

space junk

3152 silver badges6 bronze badges

2

\$\begingroup\$ Alternative solution: 𝐈Ψ𝐫𝐬 (create inclusive range, reverse each element, sum) \$\endgroup\$
– Okx
Aug 1, 2017 at 11:31
\$\begingroup\$ @Okx didn't know that the Ψ token existed! would have definitely used that in hindsight. real nice \$\endgroup\$
– space junk
Aug 1, 2017 at 12:01

Add a comment |

Giacomo Garabello · Accepted Answer · 2017-08-01 15:58:13Z

2

C (gcc), 71 bytes

q(n,x,p){p=n?q(n/10,x*10+n%10):x;}f(w,a,e){for(a=0;w;)a+=q(w--,0);e=a;}

Try it online!

answered Aug 1, 2017 at 15:58

Giacomo Garabello

1,4398 silver badges17 bronze badges

\$\begingroup\$ Wait... what? How f() returns its result without any return statement? Does the e=a instruction manipulates the registers in such a way that the result is stored in the same register than the one used by returned values? \$\endgroup\$
– scottinet
Sep 5, 2017 at 15:47

Add a comment |

Łukasz Rogalski · Accepted Answer · 2017-08-02 09:03:59Z

2

Python 3, 50 bytes

lambda n:sum(int(str(n)[::-1])for n in range(n))

Quite close to idiomatic Python code, and honestly I don't really see much room for improvement.

answered Aug 2, 2017 at 9:03

Łukasz Rogalski

1413 bronze badges

\$\begingroup\$ Use n surrounded by backticks instead of str(n) for a nice save \$\endgroup\$
– Dion
Feb 28, 2021 at 7:34
\$\begingroup\$ Backticksyntax is Python 2 only. Plus, the answer is off by 1.. it should be range(n+1) \$\endgroup\$
– movatica
Feb 28, 2021 at 22:25

Add a comment |

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

2

Excel VBA, _{80 78} 49 Bytes

Anonymous VBE Immediate Window function that takes input expected type Integer from range [A1] determines all of the values that fall within the range 1:[A1], and outputs the sum of the reversed values to the VBE immediate window

For i=1To[A1]:s=s+Val(StrReverse(Str(i))):Next:?s

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Aug 1, 2017 at 15:45

Taylor Alex Raine

8,2802 gold badges25 silver badges48 bronze badges

Add a comment |

Kaz · Accepted Answer · 2017-09-05 14:15:07Z

TXR Lisp: 62 56 bytes:

(opip(range 1)(mapcar[chain tostring reverse toint])sum)

Interactive:

1> (opip(range 1)(mapcar[chain tostring reverse toint])sum)
#<intrinsic fun: 0 param + variadic>
2> [*1 10]
46
3> [*1 999]
454545

The following 44 byte expression, inspired by the Pari/GP solution, is possible; however, it requires the sum macro to be defined:

1> (defmacro sum (var from to expr)
      (with-gensyms (accum)
        ^(for ((,var ,from) (,accum 0))
              ((<= ,var ,to) ,accum)
              ((inc ,accum ,expr) (inc ,var)))))
sum
2> (do sum x 1 @1 (toint(reverse(tostring x))))
#<interpreted fun: lambda (#:arg-01-0171 . #:rest-0170)>
3> [*2 10]
46
4> [*2 999]
454545

Giuseppe · Accepted Answer · 2017-12-14 19:35:00Z

2

Gaia, 7 bytes

@…)¦v¦Σ

Try it online!

Range, Reverse, and sum!

@             # push an input. stack: n
 …            # generate range. stack: [0...n-1]
  )¦          # map over the list with increment. stack: [1...n]
    v¦        # map over the list with reverse. stack: [1...n], but all digitally reversed
      Σ       # sum the list; output TOS.

edited Dec 14, 2017 at 19:35

answered Dec 14, 2017 at 19:14

Giuseppe

28.1k3 gold badges30 silver badges101 bronze badges

Add a comment |

Unihedron · Accepted Answer · 2017-12-14 19:35:05Z

2

Ruby, 38 35 bytes

Similar to the previous Ruby solution, but a full program and also shorter (for less than an hour)!

p (?1..gets).sum{|x|x.reverse.to_i}

Shortened by 3 bytes thanks to user akostadinov

Try it online!

Explanation

p             # Inspect and print. Written as infix notation to avoid using ()
(?1..gets)    # All strings from "1" to "input", based on successive string format
  .sum{|x|    # Enumerable -> Map to value -> Sum by value
      x.reverse.to_i
  }

edited Dec 14, 2017 at 19:35

answered Dec 14, 2017 at 17:44

Unihedron

1,28514 silver badges21 bronze badges

1

\$\begingroup\$ you can do (?1..gets).sum{...}) \$\endgroup\$
– akostadinov
Dec 14, 2017 at 18:54

Add a comment |

Axuary · Accepted Answer · 2021-04-11 16:03:40Z

2

Excel, 59 bytes

=LET(y,COLUMN(A:O),SUM((0&MID(SEQUENCE(A1),y,1))*10^(y-1)))

Explanation

=LET(
y,COLUMN(A:O)                           'y = [1..15] horz.; Excel is accurate to 15 places
SUM((0&MID(SEQUENCE(A1),y,1))*10^(y-1)) 'final result
           SEQUENCE(A1)                 '[1..A1] vertical
    (0&MID(            ,y,1))           'array of individual digits; 0& is to avoid errors on blank cells 
                             *10^(y-1)  'multiply 2nd column by 10, 3rd 100, etc.
SUM(                                  ) 'sum the array

edited Apr 11, 2021 at 16:03

answered Apr 11, 2021 at 13:18

Axuary

3,4065 silver badges11 bronze badges

\$\begingroup\$ Just an FYI, your answers are popping up in the Low Quality Posts review queue as their length catches the system filter. I'd suggest adding in a brief explanation in order to avoid this :) \$\endgroup\$
– caird coinheringaahin g ♦
Apr 11, 2021 at 13:41
\$\begingroup\$ Thank you for letting me know. I will start adding some explanations. \$\endgroup\$
– Axuary
Apr 11, 2021 at 15:53

Add a comment |

Number Basher · Accepted Answer · 2022-05-09 07:40:58Z

2

Python 3, 52 bytes

lambda n:sum(int(str(n+1)[::-1])for n in range(n))
lambda n:sum(int(f'{n+1}'[::-1])for n in range(n))

The second is equivalent to the first.

answered May 9, 2022 at 7:40

Number Basher

1,5301 gold badge5 silver badges30 bronze badges

Add a comment |

Blue · Accepted Answer · 2017-08-01 07:43:51Z

1

Pyke, 7 bytes

SF`_b)s

Try it online!

S       -   range(1, input)
 F   )  -  for i in ^:
  `     -     str(i)
   _    -    reversed(^)
    b   -   int(^)
     s  - sum(^)

answered Aug 1, 2017 at 7:43

Blue

28.5k8 gold badges50 silver badges99 bronze badges

Add a comment |

Cinaski · Accepted Answer · 2017-08-01 08:10:52Z

1

MATL, 5 bytes

:VPUs

Try it online!

answered Aug 1, 2017 at 8:10

Cinaski

2,2481 gold badge7 silver badges17 bronze badges

Add a comment |

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

1

Pyth - 7 bytes

sms_`dS

Explanation

sms_`dSQ  Q added implicitly
s         Sum of
 m        map
  s_`d    integer representation of reversal of string representation
          to
      SQ  Range from 1 to input

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Dec 30, 2017 at 5:48

Tornado547

1,1331 gold badge7 silver badges13 bronze badges

Add a comment |

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

1

Pyt, 3 bytes

ř₫Ʃ

Try it online!

The characters perform the following operations: range, reverse, sum.

edited Jun 17, 2020 at 9:04

CommunityBot

1

answered Feb 22, 2018 at 0:01

RaviRavioli

1,5762 gold badges17 silver badges41 bronze badges

\$\begingroup\$ Dammit. You beat me to it. +1 \$\endgroup\$
– mudkip201
Feb 22, 2018 at 3:55
\$\begingroup\$ @mudkip201 Yeah I feel like its almost a race to see who can get the most trivial arithmetic challenges answered \$\endgroup\$
– RaviRavioli
Feb 22, 2018 at 14:56

Add a comment |

hakr14 · Accepted Answer · 2021-02-28 07:18:47Z

1

Canvas, 7 bytes

Ｒ｛ŗ±┤］∑

Try it here!

answered Feb 28, 2021 at 7:18

hakr14

4,9641 gold badge10 silver badges18 bronze badges

Add a comment |

J. А. del Rio - слава России · Accepted Answer · 2021-03-01 00:45:49Z

1

Lua (59 bytes)

function r(u)return u<1 and 0 or(u..""):reverse()+r(u-1)end

answered Mar 1, 2021 at 0:45

J. А. del Rio - слава России

3413 silver badges6 bronze badges

Add a comment |

mazzy · Accepted Answer · 2021-04-10 11:59:03Z

1

PowerShell, 43 bytes

1.."$args"-join'+'|% t*y|%{$s=$_+$s}
$s|iex

Try it online!

This script converts a range [1,2,3,4,5,6,7,8,9,10] to the reversed string 01+9+8+7+6+5+4+3+2+1 and evaluates the string

answered Apr 10, 2021 at 11:59

mazzy

7,0652 gold badges10 silver badges22 bronze badges

Add a comment |

Giuseppe · Accepted Answer · 2021-04-10 18:43:21Z

1

R, 89 75 bytes

sum(scan(t=sapply(1:scan(),function(x)intToUtf8(rev(utf8ToInt(c(x,'')))))))

Try it online!

Thanks to JayCe and Dominic van Essen for the golfs.

edited Apr 10, 2021 at 18:43

answered Aug 1, 2017 at 15:17

Giuseppe

28.1k3 gold badges30 silver badges101 bronze badges

\$\begingroup\$ I know it's an old one but what about this for 82 bytes? \$\endgroup\$
– JayCe
Jun 1, 2018 at 17:53
\$\begingroup\$ or even this for 75 bytes? \$\endgroup\$
– Dominic van Essen
Apr 10, 2021 at 12:44
\$\begingroup\$ @DominicvanEssen thanks! \$\endgroup\$
– Giuseppe
Apr 10, 2021 at 18:43
\$\begingroup\$ @JayCe Doesn't seem like you're active any longer, but thank you for the golf, and apologies I didn't respond sooner! \$\endgroup\$
– Giuseppe
Apr 10, 2021 at 18:44

Add a comment |

Symmetr1cGroup · Accepted Answer · 2021-04-10 20:59:58Z

1

Python 3, 127 bytes

def f(n):
 s=0
 for i in range(1,n+1):
  r=""
  k=str(i)
  for j in range(0,len(k)):
   r=r+k[len(k)-1-j]
  s+=int(r)
 return s

edited Apr 10, 2021 at 20:59

answered Apr 10, 2021 at 20:40

Symmetr1cGroup

611 gold badge1 silver badge5 bronze badges

Add a comment |

Donat · Accepted Answer · 2021-04-10 22:22:13Z

1

Java (OpenJDK 8), 81 bytes

long g(int n){return n<1?0:new Long(""+new StringBuffer(""+n).reverse())+g(n-1);}

Try it online!

answered Apr 10, 2021 at 22:22

Donat

1,4395 silver badges10 bronze badges

Add a comment |

ZippyMagician · Accepted Answer · 2021-04-11 02:42:37Z

1

Arn `-x`, 4 bytes

P▀g³

Try it!

Explained

Unpacked: ~)@.<

    ~    One-range to
      _  Input; implied
  )
@        Map with
  .<     Reverse fix
      Implicit sum

answered Apr 11, 2021 at 2:42

ZippyMagician

1,6317 silver badges11 bronze badges

Add a comment |

chunes · Accepted Answer · 2022-05-03 20:18:46Z

1

Factor + `math.unicode`, 39 bytes

[ [1..b] [ >dec reverse dec> ] map Σ ]

Using build 2166 for the somewhat recent addition of >dec.

edited May 3, 2022 at 20:18

answered May 3, 2022 at 19:52

chunes

22.8k3 gold badges21 silver badges51 bronze badges

Add a comment |

DeathIncarnate · Accepted Answer · 2022-05-03 20:29:58Z

1

Burlesque, 7 bytes

ro)<-++

Try it online!

ro  # Range
)<- # Reverse
++  # Sum

answered May 3, 2022 at 20:29

DeathIncarnate

2,5506 silver badges9 bronze badges

Add a comment |

naffetS · Accepted Answer · 2022-05-04 00:42:28Z

1

Desmos, 72 70 bytes

l=floor(logx)
f(y)=∑_{x=1}^y∑_{n=0}^lmod(floor(x/10^n),10)10^{l-n}

Try it on Desmos!

-2 bytes thanks to Aiden Chow

edited May 4, 2022 at 0:42

answered May 3, 2022 at 19:37

naffetS

12.2k2 gold badges17 silver badges48 bronze badges

Add a comment |

MarcMush · Accepted Answer · 2022-05-09 10:01:37Z

1

Julia 1.0, 38 bytes

!x=sum(Meta.parse∘join∘digits,1:x)

Try it online!

this works because digits returns an array with the digits starting with the least significants first (digits(123) == [3, 2, 1])

alternative, also 38 bytes (but more chars and not as nice)

!x=sum(@.parse(Int,join(digits(1:x))))

Try it online!

answered May 9, 2022 at 10:01

MarcMush

6,26511 silver badges16 bronze badges

Add a comment |

oeuf · Accepted Answer · 2022-07-09 02:12:49Z

1

K (ngn/k), 15 14 13 bytes

{+/.'|'$1+!x}

Try it online!

-1 byte thanks to coltim

edited Jul 9, 2022 at 2:12

answered May 5, 2022 at 13:49

oeuf

1,7933 silver badges18 bronze badges

\$\begingroup\$ You could use .' instead of `I$ to save a byte. A couple more could be saved by making this tacit, i.e. +/.'|'$1+!: \$\endgroup\$
– coltim
May 15, 2022 at 18:04

Add a comment |

Jordan · Accepted Answer · 2022-12-12 20:52:19Z

1

J-uby, 16 bytes

:+|:sum+(S|:~|Z)

Attempt This Online!

Explanation

Same idea as the Ruby answers but J-uby helps us out with some handy shortcuts.

:+ | :sum + (S | :~ | Z)

:+ |                      # Make range 1..n, then
     :sum + (          )  # Sum of items...
             S |          #   Converted to string, then
                 :~ |     #   Reversed, then
                      Z   #   Converted to int

edited Dec 12, 2022 at 20:52

answered Nov 21, 2022 at 0:38

Jordan

9,7261 gold badge30 silver badges47 bronze badges

Add a comment |

Emigna · Accepted Answer · 2022-12-14 12:32:03Z

1

><>, 68 bytes

1:{:})?^:9)?v:1+!
a:v?(1:[2$0:<.17-%1:,a}+*a{%
0.>~]$d
=?n+a3.>~{~l1

Try it online!

answered Dec 14, 2022 at 12:32

Emigna

52.9k5 gold badges42 silver badges162 bronze badges

Add a comment |

Shaggy · Accepted Answer · 2022-12-14 12:49:18Z

1

Japt `-x`, 4 bytes

õÈìÔ

Try it

õÈìÔ     :Implicit input of integer
õ        :Range [1,input]
 È       :Map
  ì      :  Convert to digit array
   Ô     :  Reverse and implicitly convert back
         :Implicit output of sum of resulting array

answered Dec 14, 2022 at 12:49

Shaggy

41.6k4 gold badges34 silver badges92 bronze badges

Add a comment |

Range, Reverse, Sum!

86 Answers 86

Pyth, 8 6 bytes

Tcl, 66 bytes

Neim, 4 bytes

Explanation

C (gcc), 71 bytes

Python 3, 50 bytes

Excel VBA, 80 78 49 Bytes

TXR Lisp: 62 56 bytes:

Gaia, 7 bytes

Ruby, 38 35 bytes

Explanation

Excel, 59 bytes

Python 3, 52 bytes

Pyke, 7 bytes

MATL, 5 bytes

Pyth - 7 bytes

Pyt, 3 bytes

Canvas, 7 bytes

Lua (59 bytes)

PowerShell, 43 bytes

R, 89 75 bytes

Python 3, 127 bytes

Java (OpenJDK 8), 81 bytes

Arn -x, 4 bytes

Explained

Factor + math.unicode, 39 bytes

Burlesque, 7 bytes

Desmos, 72 70 bytes

Julia 1.0, 38 bytes

alternative, also 38 bytes (but more chars and not as nice)

K (ngn/k), 15 14 13 bytes

J-uby, 16 bytes

Explanation

><>, 68 bytes

Japt -x, 4 bytes

Your Answer

Sign up or log in

Post as a guest

Not the answer you're looking for? Browse other questions tagged code-golfnumberarithmetic or ask your own question.

Linked

Related

Hot Network Questions

Excel VBA, _{80 78} 49 Bytes

Arn `-x`, 4 bytes

Factor + `math.unicode`, 39 bytes

Japt `-x`, 4 bytes

Not the answer you're looking for? Browse other questions tagged
code-golf
number
arithmetic
or ask your own question.