Solve for N from input string

Question

Challenge :

Your job is to find the given number N.

Input :

You will be given a string in the following form:

dN ± Y = X

Where:

d, N, X, Y are all numbers with d , X , Y being integers (not decimals).

Output :

Solve the equation and output the value of N rounded. Round up if decimal is greater than or equal to 0.5 and round down if less than 0.5

Examples :

Input Output N + 1 = 3 ---> 2 N - 1 = 5 ---> 6 2N + 1 = 3 ---> 1 2N + 1 = 4 ---> 2

Winning criteria :

This is code-golf so the shortest code in each language wins.

Notes :

Answer must be rounded it cannot be a float
Whitespace do not matter. You can have every element in the string separated by white space if you want or if you don't want leave it as it is.
You do not need to check for invalid input. i.e. All inputs will be strings in the given format.

Comments are not for extended discussion; this conversation has been moved to chat. — user45941
– user45941, Commented Apr 19, 2018 at 2:31
@Mego : I have (hopefully) made it more clear. Can you kindly take a look and open it? — Muhammad Salman
– Muhammad Salman, Commented Apr 19, 2018 at 7:08
@MuhammadSalman I'll leave both the original and add the alternative [-128,127] range answer then. (And I will delete some of my answers now, thanks for answering them.) — Kevin Cruijssen
– Kevin Cruijssen, Commented May 25, 2018 at 12:26
Can d , X , and Y be negative? what is the maximum value that needs to be handled? — Taylor Raine
– Taylor Raine, Commented May 25, 2018 at 13:23

ovs · Accepted Answer · 2018-04-16 19:06:24Z

5

Python 2, 88 74 70 bytes

-14 bytes thanks to Chas Brown.
-4 bytes thanks to Sunny Patel.

d,w,Y,_,X=input().split() print round((int(X)-int(w+Y))/float(d[:-1]))

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edited Apr 16, 2018 at 19:06

answered Apr 16, 2018 at 18:45

ovs

61.2k3 gold badges49 silver badges164 bronze badges

\$\begingroup\$ @ovs : He he broke it. If I remove even a single space bam. It blows up. This is whitespace sensitive. \$\endgroup\$

Muhammad Salman
– Muhammad Salman

2018-04-16 18:54:23 +00:00
Commented Apr 16, 2018 at 18:54
\$\begingroup\$ @MuhammadSalman This was the case before. This solution requires at least one space between the different parts. If this is not allowed I will delete my answer. \$\endgroup\$

ovs
– ovs

2018-04-16 19:02:24 +00:00
Commented Apr 16, 2018 at 19:02
\$\begingroup\$ @ovs: Na it is perfectly alright. \$\endgroup\$

Muhammad Salman
– Muhammad Salman

2018-04-16 19:04:16 +00:00
Commented Apr 16, 2018 at 19:04

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DanielIndie · Accepted Answer · 2018-04-17 03:28:47Z

under the assumption (according to comments) that we deal only with digits

JavaScript (Node.js), 30 bytes

*thanks for @Rick Hitchcock for pointing out i can use 1 instead of space (reduces 13 bytes

x=>(x[3]+x[5]-x[9])/-x[0]+.5|0

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Sunny Patel · Accepted Answer · 2018-04-16 20:53:14Z

Python 2, 64 63 bytes

Using eval

d,w,Y,_,X=input().split() print-eval('('+w+Y+'-'+X+')/'+d[:-1])

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Saved 1 byte thanks to Keyu Gan

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

Java 10, 111 94 (or 92) bytes

s->{var a=s.split("N|=");return(int)((new Float(a[2])-new Float(a[1]))/new Float(a[0])+.5);}

Input is in the format dN±Y=X (without any spaces) instead of dN ± Y = X.

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2 more bytes could be saved if the numbers are never outside the [-128, 127] range, in which case the last and one of the two first Float can be changed to Byte.
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Explanation:

s->{ // Method with String parameter and integer return-type var a=s.split("N|="); // And split by "N" or "=" to a String-array return(int)((new Float(a[2]) // Return the third number (after the equal sign), -new Float(a[1])) // minus the second number (including leading +/-), /new Float(a[0]) // divided by the first number +.5);} // Rounded by using `(int)(R + 0.5)`

Shaggy · Accepted Answer · 2023-05-09 10:42:52Z

Japt v2.0a0, 20 bytes

q/N|=/ f o!-Uo)r!÷ r

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q/N|=/ f\no!-Uo)r!÷ r :Implicit input of string U : e.g. "2N+1=4" "N+1=4" q :Split on /N|=/ : "N" or "=" > ["2","+1","4"] ["","+1","4"] f :Filter (removes the first element if the string started with "N") > ["2","+1","4"] ["+1","4"] \n :Reassign to U Uo :Pop last element (X) > "4" "4" o :Modify last element (Y) !- :X-Y > ["2",3] [3] r :Reduce by !÷ : Inverse division > 1.5 3 r :Round > 2 3

Keyu Gan · Accepted Answer · 2018-04-16 20:12:27Z

1

Wolfram Language (Mathematica), 54 46 bytes

Round[ToExpression[""<>(#/."="->"-")]~Root~1]&

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edited Apr 16, 2018 at 20:12

answered Apr 16, 2018 at 19:01

Keyu Gan

2,16312 silver badges25 bronze badges

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Yair Rand · Accepted Answer · 2018-04-17 04:52:37Z

JavaScript (Node.js), 44 bytes

x=>([m,a,r]=x.split(/N|=/),r-a)/(+m||1)+.5|0

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Or, for only single-digit numbers:

JavaScript (Node.js), 36 bytes

([m,,o,a,,r])=>-(o+a-r)/(+m||1)+.5|0

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GPS · Accepted Answer · 2018-04-18 07:13:44Z

C (clang), 133 bytes

N,d,y,x,a[9],o;f(*s){sscanf(s," %[0-9N] %c %d = %d",a,&o,&y,&x);d=!sscanf(a,"%d",&d)?1:d;N=(x-(o>43?-y:y))*2/d;printf("%d",N/2+N%2);}

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This handles all spaces except between d and N.

[Removed wrong answer that rounds down]

\$\begingroup\$ some spaces can be removed \$\endgroup\$

l4m2
– l4m2

2018-05-26 01:41:17 +00:00
Commented May 26, 2018 at 1:41 — l4m2
– l4m2, Commented May 26, 2018 at 1:41
\$\begingroup\$ 124 bytes \$\endgroup\$

ceilingcat
– ceilingcat

2018-11-23 19:43:16 +00:00
Commented Nov 23, 2018 at 19:43 — ceilingcat
– ceilingcat, Commented Nov 23, 2018 at 19:43

Jo King · Accepted Answer · 2018-04-18 21:24:54Z

1

Befunge-93 (FBBI), 34 26 bytes

&~$~90p0&X&-2*\/-:2%\2/+.@

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If we didn’t need to bother with rounding correctly, it could be much smaller:

&~$~90p0&X&-\/-.@

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-\/-

edited Apr 18, 2018 at 21:24

answered Apr 17, 2018 at 5:16

Jo King

48.1k6 gold badges131 silver badges187 bronze badges

\$\begingroup\$ I think this fails to round, and instead truncates. For example, it returns 0 for 3N+1=3 when it should round 2/3 up to 1 \$\endgroup\$

MercyBeaucou
– MercyBeaucou

2018-04-17 21:45:51 +00:00
Commented Apr 17, 2018 at 21:45
\$\begingroup\$ Fixed <padding> \$\endgroup\$

Jo King
– Jo King

2018-04-18 07:16:45 +00:00
Commented Apr 18, 2018 at 7:16
\$\begingroup\$ For rounding, you can double the numerator before dividing, add the quotient to itself mod 2, and then divide the sum of that by 2, instead of doing the multiply by 10 thing \$\endgroup\$

MercyBeaucou
– MercyBeaucou

2018-04-18 21:11:33 +00:00
Commented Apr 18, 2018 at 21:11
\$\begingroup\$ np, always happy to help \$\endgroup\$

MercyBeaucou
– MercyBeaucou

2018-04-18 23:40:44 +00:00
Commented Apr 18, 2018 at 23:40

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Taylor Raine · Accepted Answer · 2018-05-25 13:30:38Z

Yabasic, 142 bytes

An anonymous function that takes input as a string and outputs to the console.

Line Input""s$ dim n$(5) k=token(s$,n$()) n$=n$(1) If n$="N"n$=("1N") ?Int((Val(n$(5))-Val(n$(2)+"1")*Val(n$(3)))/Val(Left$(n$,Len(n$)-1))+.5)

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lyxal · Accepted Answer · 2023-05-09 03:29:06Z

Vyxal, 110 bits¹, 13.75 bytes

‛Nx*\=/ƒ∆qh.1+ṙ

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Python rounding is a little goofy hence the .1+ṙ at the end.

Could be 9.125 bytes: ‛Nx*\=/ƒ∆q if it wasn't for rounding.

Explained

‛Nx*\=/ƒ∆qh.1+ṙ ‛Nx* # Replace all N with x \=/ # split on equal sign ƒ∆q # and solve the equation for x. Yes. There's a built in for it. h.1+ # add 0.1 to the result to account for the fact that python seems to round down if <= 0.5 instead of < 0.5 ṙ # round the answer as required

138 Aspen · Accepted Answer · 2023-05-09 03:31:01Z

Scala 3, 168 bytes

import java.lang._ import scala.util.chaining._ val c:String=>Int=_.split("N|=").pipe(a=>(new Float(a(2))-new Float(a(1)))/new Float(a(0))).pipe(x=>math.round(x).toInt)

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I thought scala._ and java.lang._ were imported by default — user
– user, Commented May 11, 2023 at 3:17

Ferro Luca · Accepted Answer · 2023-05-09 07:08:58Z

[Matlab], 91 bytes

this is the most resilient version.

assuming that s is the input string.

syms N;v=str2double(regexp(s,'(?<!\d)(\d)+(?!\d)','match'));round(solve(v(1)*N+v(2)==v(3)))

[Matlab], 74 bytes

syms N;round(solve(str2double(s(1))*N+str2double(s(4))==str2double(s(6))))

but doesnt really work if for example Y was 2 digits (ie 10). I'll try to improve it a bit.

[Matlab], 29 bytes

if the input was just the numbers and not a string

sym N;round(solve(d*N+Y==X))

GamrCorps · Accepted Answer · 2018-04-16 18:57:50Z

0

Convex, 19 bytes

S-®-?\d+"ô:d~\-\/mo

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answered Apr 16, 2018 at 18:57

GamrCorps

7,6822 gold badges30 silver badges61 bronze badges

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Ethan · Accepted Answer · 2018-04-16 19:24:09Z

PHP, 45 bytes

<?=round((($s=$argn)[3].$s[5]-$s[9])/-$s[0]);

Run with echo '<input>' | php -nF <filename> or Try it online.

This requires that d always be given, and that the string is the same length each time, e.g.:

N + 1 = 3 won't work, but 1N + 1 = 3 will work.
1N +1 =3 won't work, but 1N + 1 = 3 will work.

Bolce Bussiere · Accepted Answer · 2018-04-16 22:19:48Z

J, 26 Bytes

<.({.%~{:-1&{)".>0 2 4{cut

Note that the result for N is floored (not rounded), so for the last test case it returns 1 instead of 2. If this is unacceptable I will change the answer.

Input should be of the form 'd N +-Y = X'

Explanation:

 cut '10 N +2 = 23' NB. Split on whitespace ┌──┬─┬──┬─┬──┐ │10│N│+2│=│23│ └──┴─┴──┴─┴──┘ 0 2 4{cut '10 N +2 = 23' NB. Choose relevant portions ┌──┬──┬──┐ │10│+2│23│ └──┴──┴──┘ ".>0 2 4{cut '10 N +2 = 23' NB. Eval each 10 2 23 ({.%~{:-1&{)".>0 2 4{cut'10 N +2 = 23' NB. Compute (x-y)/d 2.1 <.({.%~{:-1&{)".>0 2 4{cut'10 N +2 = 23' NB. Floor 2

lee · Accepted Answer · 2018-04-18 04:03:28Z

C# (149 Bytes)

s=>(int)Math.Round(((s=s.Replace(" ",""))[s.Length-1]-48-((s.Contains("-")?-1:1)*(s.Split(new[]{'+','-'})[1][0]-48)))/(decimal)(s[0]=='N'?1:s[0]-48))

Craptacular bloated C# solution. Guess I could've ported the Java solution but I try not to look at others' stuff before posting mine, so here we are.

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Asone Tuhid · Accepted Answer · 2018-04-18 08:17:24Z

0

Ruby, 66 bytes

->s{a,_,b,_,c=s.split.map &:to_f;((s[?+]?c-b:c+b)/(a+0**a)).round}

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answered Apr 18, 2018 at 8:17

Asone Tuhid

2,4139 silver badges23 bronze badges

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PieCot · Accepted Answer · 2018-04-18 20:20:26Z

awk, 48 bytes

awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}'

Use cases:

echo "N + 1 = 3" | awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}' echo "N - 1 = 5" | awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}' echo "2N + 1 = 3" | awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}' echo "2N + 1 = 4" | awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}'

Extra case:

echo "3N + 1 = 11" | awk -F'[ N]' '{printf("%.f",($6-$4)/($1?$1:1))}'

Output: 3

Francisco Hahn · Accepted Answer · 2018-05-25 15:12:37Z

PHP, 83 Bytes

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For some reason round does not round to the closest integer on tio run, on this version the solution has some extra bytes (87 Bytes)

Code

<?=round(($c=explode(" ",$argv))[4]-($c[1].$c[2]))/($c[0]==N?1:substr($c[0],0,-1));

Explanation

//ecuation structure xN sign c = m //array structure like ["xN","sign", "c", "=", "m"] round( //round the result ( //first element of the ecuation $c=explode(" ",$argv))[4] //explode the string and get the 4th value - //substract, php accepts (1-(-1)) so, //it can ve solved like this ($c[1].$c[2]) //concat the sign with c ) / //divide by x ($c[0]==N?1:substr($c[0],0,-1) //if the first element xN it's N //divide by 1, else remove N and divide );

Question

About negative numbers, my code should work for an equation like -xN +- c = m, but when you are considering a x = -1, the input will be -N +- c = m or -1N +- c = m?

JayCe · Accepted Answer · 2018-05-25 19:02:57Z

R, 90 bytes

-round(eval(parse(t=gsub("=","-",gsub("\\dN","",s<-scan(,"")))))/(gsub("N.*$","",s):1)[1])

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Assumes d is present as per the spec. Probably not the shortest option - I am sure there are better regex.

RARE Kpop Manifesto · Accepted Answer · 2023-05-09 02:27:50Z

awk : safe division without branching ternary condition

echo 'N + 1 = 3' | gawk '$__=sprintf("%.f",($5-($2$3))/(_+=$_)^!!_)' mawk '{printf("%.f",($5-($2$3))/(_+=$_)^!!_)}'

echo '2N + 1 = 4' | nawk '$!NF=sprintf("%.f",($5-($2$3))/(_+=$!_)^!!_)'

Stack Exchange Network

Solve for N from input string

Challenge :

Input :

Output :

Examples :

Winning criteria :

Notes :

22 Answers 22

Python 2, 88 74 70 bytes

JavaScript (Node.js), 30 bytes

Python 2, 64 63 bytes

Java 10, 111 94 (or 92) bytes

Japt v2.0a0, 20 bytes

Wolfram Language (Mathematica), 54 46 bytes

JavaScript (Node.js), 44 bytes

JavaScript (Node.js), 36 bytes

C (clang), 133 bytes

Befunge-93 (FBBI), 34 26 bytes

Yabasic, 142 bytes

Vyxal, 110 bits¹, 13.75 bytes

Explained

Scala 3, 168 bytes

[Matlab], 91 bytes

[Matlab], 74 bytes

[Matlab], 29 bytes

Convex, 19 bytes

PHP, 45 bytes

J, 26 Bytes

Explanation:

C# (149 Bytes)

Ruby, 66 bytes

awk, 48 bytes

PHP, 83 Bytes

R, 90 bytes

Hot Network Questions

Solve for N from input string

Challenge :

Input :

Output :

Examples :

Winning criteria :

Notes :

22 Answers 22

Python 2, 88 74 70 bytes

JavaScript (Node.js), 30 bytes

Python 2, 64 63 bytes

Java 10, 111 94 (or 92) bytes

Japt v2.0a0, 20 bytes

Wolfram Language (Mathematica), 54 46 bytes

JavaScript (Node.js), 44 bytes

JavaScript (Node.js), 36 bytes

C (clang), 133 bytes

Befunge-93 (FBBI), 34 26 bytes

Yabasic, 142 bytes

Vyxal, 110 bits1, 13.75 bytes

Explained

Scala 3, 168 bytes

[Matlab], 91 bytes

[Matlab], 74 bytes

[Matlab], 29 bytes

Convex, 19 bytes

PHP, 45 bytes

J, 26 Bytes

Explanation:

C# (149 Bytes)

Ruby, 66 bytes

awk, 48 bytes

PHP, 83 Bytes

R, 90 bytes

Related

Hot Network Questions

Vyxal, 110 bits¹, 13.75 bytes