string length comparer [closed]

Question

this program has to take two strings and compare their length, then tell you which one is longer (string-a or string-b) and by how much

rules:

• no using .length or other built-in length checking methods (duh!)
• no using addition or subtraction, this includes improvised addition/subtraction, in case you find some sort of weird improvisation.
• no > / < (greater then/less then) inside if / if-else statements (you can use them in loops though), this obviously includes >= etc. and no cheating (bool = a > b;if(bool))
• emphasis is on short rather then efficient code
• oh yeah almost forgot... good luck!

Answer 1

SED, 45 (43 + 2 for the -n flag)

s/./a/g
h
n
s/./b/g
G
:a
s/b\(.*\)a/\1/
ta

Expects input as two separate lines, outputs the difference in unary, using "a" or "b" to indicate the longer string. run with sed -n.

Answer 2

Perl, 87 78 - tells which is longer and by how much

alternative:

• 72 - tells which is longer and by how much, no special message if equal

---

Perl script expecting 2 strings as command line arguments. Tells which one is longer and by how much. This one I tried to make it readable and not short.

#!/usr/bin/perl
use warnings;
use strict;

my ($x,$y)=@ARGV;
$x=$x=~s/.//g;
$y=$y=~s/.//g;
my @z=($x..$y);
my @w=($y..$x);
if (@z) {
    if ($#z) { print "2nd longer than 1st by $#z" }
    else { print "Equal length" }
}
else {
    print "1st longer than 2nd by $#w"
}

Same code as a one liner, counting 78 characters (output now prints "a3" if a > b by 3 characters, "0" if equal):

perl -E'($x,$y)=@ARGV;$_=s/.//g for$x,$y;@z=$x..$y;@w=$y..$x;say@z?$#z?"b$#z":0:"a$#w"'

Finally, since OP clarified that when they are equal it is not really important what it will print, we can save 6 more characters:

perl -E'($x,$y)=@ARGV;$_=s/.//g for$x,$y;@z=$x..$y;@w=$y..$x;say@z?"b$#z":"a$#w"'

Answer 3

Tcl 8.6, 90

lmap c [split $a {}] d [split $b {}] {puts [expr {{}eq$d?{A}:{}eq$c?{B}:[continue]}];exit}

If you run Tcl 8.5, use foreach instead lmap.

This shows a nice feature of Tcl's foreach/lmap: It can walk over several lists at once.

Answer 4

J 17

Since there is no output specification: the length difference is outputted at the location of the shortest string

    longest =: *&.^/"1@(=&' ')@,:
    'foobar' longest 'abc'
0 3 NB. Means abc is shorter by 3 chars.

Answer 5

Javascript 96 92

x=prompt;i=c=0;for(p=x();c=p[i=-~i];);q=x();for(j=0;c=q[i=~-i,j=-~j];);alert(0<i&&p+i||q+-i)

Note 0<i&& contains no if statement but a logical operator, which is not forbidden.

Input asd,asdfg Output asdfg2

Means asdfg is 2 characters longer.

Answer 6

Bringing up the rear as always with the verbose language. :)

Java - 278

import java.util.*;class b{public static void main(String[]a){Stack z=new Stack(),y=new Stack();for(String q:a[0].split(""))z.push(q);for(String q:a[1].split(""))y.push(q);while(!z.empty()&&!y.empty()){z.pop();y.pop();}System.out.print(y.empty()?"1-"+z.size():"2-"+y.size());}}

With line breaks and tabs

import java.util.*;
class a{
    public static void main(String[]a){
        Stack z=new Stack(),y=new Stack();
        for(String q:a[0].split(""))z.push(q);
        for(String q:a[1].split(""))y.push(q);
        while(!z.empty()&&!y.empty()){
            z.pop();
            y.pop();
        }
        System.out.print(y.empty()?"1-"+z.size():"2-"+y.size());
    }
}

Answer 7

Ruby, 66 52 (shows only which one is longer)

f=->{gets.gsub(/./,?1)}
a=f[]
b=f[]
puts'sab'[a<=>b]

Prints s for same, a for string a, and b for string b.

Ruby, 184 173 146 143 139 140 (also shows how much longer it is)

f=->{gets.gsub(/./,?1)}
a=f[]
b=f[]
d=->e{Math.log10(e.to_i).floor.next.to_s}
puts(a==b ? ?s:(c=a.sub(b,''))!=a ? ?a+d[c]:?b+d[b.sub(a,'')])

Sample run:

c:\a\ruby>stringcmp
testing123
testing
a3

c:\a\ruby>stringcmp
codegolf.SE
code golf . stack exchange
b15

c:\a\ruby>stringcmp
test
test
s

c:\a\ruby>

Answer 8

Mathematica 40

f = #~Count~0 & /@ PadLeft[Characters /@ {##}] &

Output is similar to the J version.

Example Usage:

f["looooong", "short"]

{0, 3}

f["short", "thisstringisveryverylong"]

{19, 0}

f["equal", "equal"]

{0, 0}

Answer 9

PHP (44)

-r'list(,$a,$b)=$argv;echo strcmp($a^$a,$b^$b);'

• The -r argument and single quotes are not counted in the score.
• string-a and string-b are accepted as command-line arguments.
• The magnitude of the decimal number printed is the difference in length.
• The sign indicates which string is longer. A positive number means string-a is longer. A negative number means string-b is longer. Zero means the strings are the same length.

PHP 5.4 (96)

Here, strcmp is avoided in favor of other string functions that are not so cheap.

-r'list(,$a,$b)=$argv;echo@strtr(explode(${"\3"^$c=trim(($a^=$a).b^($b^=$b).a)},$$c,2)[1],"\0",$c);'

• Scoring and input format remain the same.
• The difference in length is printed in unary.
• The symbol a is used if string-a is longer; b is used if string-b is longer.
• Nothing is printed if the strings are the same length (except in the commented version, which omits the error suppression operator @ and thus may report PHP notices and warnings).

Commented code:

<?php

list(, $a, $b) = $argv;

// Replace all bytes in both $a and $b with null bytes
// (Anything XORed with itself is zero.)
$a ^= $a;
$b ^= $b;

// PHP's bitwise XOR truncates its output to the shorter string's length,
// so only the marker ('a' or 'b') appended to the shorter string will
// remain after the null bytes in common are trimmed off. If $a is shorter,
// 'b' remains; likewise, if $b is shorter, 'a' remains.
$longer = trim($a . 'b' ^ $b . 'a'); // $c in the golfed code

// Flip bits 0 and 1 to switch 'a' to 'b' (or 'b' to 'a')
// ('a' === chr(0b1100001); 'b' === chr(0b1100010); "\3" === chr(0b11))
$shorter = "\3" ^ $longer;

// Remove the shorter string from the longer string
// $$shorter refers to $a if $shorter === 'a' or $b if $shorter === 'b'.
// $$longer works the same way.
$difference = explode($$shorter, $$longer, 2)[1];

echo strtr($difference, "\0", $longer);

Answer 10

JavaScript (prompt for input) - 128

I golfed it 2 more characters.

p=prompt,f=alert,i='lastIndexOf'
a=p().replace(/./g,'.')
b=p().replace(/./g,'.')
j=a[i](b),k=b[i](a)
~j&&f('a '+j)
~k&&f('b '+k)

Answer 11

Python - 291 261 244 223 220 210 206

I got 206

import sys,itertools
q=sys.argv
h=[]
i=0
for k,g in itertools.groupby(map(lambda f,b:2 if f is None else 1 if b is None else 0,q[1],q[2])):h.append(list(g))
for i,a in enumerate(h[1],1):0
print q[h[1][0]],i

Sample Run

C:\pjs\codegolf>python last.py bananas apples
bananas 1
C:\pjs\codegolf>python last.py bananas hazlenuts
hazlenuts 2

Answer 12

Bending the rules some...

JavaScript (92)

p=prompt
~function f(a,b) {
   a && !b && alert(0)
  !a &&  b && alert(1)

  f(a.slice(1), b.slice(1))
}(p(),p())

(Minified: p=prompt;~function f(a,b){a&&!b&&alert(0);!a&&b&&alert(1);f(a.slice(1),b.slice(1))}(p(),p()))

Takes two strings via prompts. Alerts the difference in unary (as with Hasturkun's solution), using 0s if the first string is longer and 1s if the second string is longer. Outputs each digit in a separate alert (ow), and terminates eventually when the call stack runs out (owww).

If we ignore the rule about no addition or subtraction, we could easily have the number be a nice (base 10) number whose sign denotes which string is longer:

p=prompt
alert(function f(a,b,n) {
  return a || b? f(a.slice(1), b.slice(1), n - !a + !b)
       :         n
}(p(),p(),0))

This version doesn't even wait for the call-stack to overflow!

Answer 13

Perl, 69 characters

sub l{l(map{substr$_,1}@_)if$_[0]&&$_[1];say pop()?2:1;die}l(<>,<>)

The gist is, recurse until one string is empty, then print the other. Run with perl -e CODE 2> /dev/null

Answer 14

Python 3: 125 91 90

Finally beat the JavaScript solutions :)

Prints both which is longer, and by how much.

Current (90 and Python 3):

I=input
q=a,b=I(),I()
while a+b:s=q[b!=""];a=a[1:];b=b[1:];i=a and b and-1or-~i
print(s,i)

Example output:

rees@Rees-Ubuntu:~/Python/CodeGolf$ python3 StringComparer.py
hi <- input one
hello <- input two
hello 3 <- output

Old (125 and Python 2):

r=raw_input
q=a,b=r(),r()
while a and b:a=a[1:];b=b[1:]
s=(q[0],q[1])[a==""]
i=0
while a or b:a=a[1:];b=b[1:];i=-~i
print s,i

Answer 15

Python, 708, 570, 566, 462, 492, 481, 480, 475, 363, 357, 354, 346, 343, 341, 340, 327, 315 (with whitespace)

My first CG, be gentle:

import sys
c=[1,2]
a=o=[]
l=d=e=v=0
s=sys.argv
r=range(0,99)
a=[zip(list(s[x]),r[1:]) for x in c]
a.insert(0,0)
for x in c:
    for p in a[x]:
        try:
            v=a[x==2 and 1 or 2][p[1]]
        except:
            l=s[x]
            o.append(1)
            e=1
    if e:break
o=zip(o,r)
print[l,o.pop()[1]]

Sample run:

me@home:~$ python diff.py bananas apples
['bananas', 1]
me@home:~$ python diff.py bananas hazlenuts
['hazlenuts', 2]

Answer 16

C, 230 200 193 characters

EDIT: Shortened it from 230 to 193 characters.

My first golf attempt. Maybe not a hole-in-one, but it works. Not being allowed to use strlen for this forces it to be fairly verbose in C. Maybe it can be shortened a bit?

a,b,w,i,l;
int main(int c,char **v){
    for(;a<256||b<256;i++){
        if(!v[1][i])a|=256;
        if(!v[2][i])b|=256;
        if(!(a&256))a++;
        if(!(b&256))b++;
    }
    a&=255;b&=255;
    w=a>b?0:1;
    l=w?b-a:a-b;
    printf("%s %i\n",v[w+1],l);
}

Or the uglier version:

a,b,w,i,l;int main(int c,char **v){for(;a<256||b<256;i++){if(!v[1][i])a|=256;if(!v[2][i])b|=256;if(!(a&256))a++;if(!(b&256))b++;}a&=255;b&=255;w=a>b?0:1;l=w?b-a:a-b;printf("%s %i\n",v[w+1],l);}

Example output:

N:\>golf.exe everything works
everything 5

Answer 17

Powershell 140 (assumes a max difference of 999)

$c=@(compare($args[0]-split'.')($args[1]-split'.'))
$n=[collections.stack]@(999..1)
$c|%{$n.pop()}
if($c){$args[$c[0].sideindicator-eq'=>']}

Outputs nothing if the string lengths are equal. If the string lengths are not equal, the longer string is displayed; the last number is the difference.

Answer 18

C (gcc), 89 bytes

i;c;q;j;f(a,b)char*a,*b;{for(i=j=c=0;a[i]||b[j];a[i]&&++i,b[j]&&++j)a[i]&&b[j]?:++c;a=c;}

Try it online! I think this has room for improvement, but I'm not sure where. Abuses undefined behaviour, but it it Works On TIO™. Simply starts increment c when one of a[i] or b[j] is the null byte (the end of the string); i and j are incremented until they hit this null byte.

Answer 19

Clojure - 206

(defn is-longer [first second first-left second-left]
  (defn remaining [current count]
    (if (empty? current)
      (/ (Math/log count) (Math/log 2))
      (remaining (rest current) (bit-shift-left count 1))))
  (cond
   (empty? first-left) [2 (remaining second-left 1)]
   (empty? second-left) [1 (remaining first-left 1)]
   :else (is-longer first second (rest first-left) (rest second-left))))

Or minified:

(defn y [a b al bl] (defn x [u t] (if (empty? u) (/ (Math/log t) (Math/log 2)) (x (rest u) (bit-shift-left t 1)))) (cond (empty? al) [2 (x bl 1)] (empty? bl) [1 (x al 1)] :else (y a b (rest al) (rest bl))))

Or in prettierific:

Returns: [1|2 count]

Getting around not using + was a fun challenge.

Answer 20

Python, 194

import sys,itertools as T
A=sys.argv
B=[]
N,i=None,0
for k,g in T.groupby(map(lambda f,b:[[0,1][b is N],2][f is N],A[1],A[2])):B.append(list(g))
for i,j in enumerate(B[1],1):0
print A[B[1][0]],i

Answer 21

R - 120/114

Shows difference:

a=strsplit(scan(what='c'),"")
c=0
for(i in 1:2){for(y in a[[i]]){if(i-1)c=c+1 else c=c-1}}
d=abs(c)
cat(a[[(c==d)+1]],d)

Shows just the longer:

a=strsplit(scan(what='c'),"")
c=0
for(i in 1:2){for(y in a[[i]]){if(i-1)c=c+1 else c=c-1}}
cat(a[[(c==abs(c))+1]])