Generate a one-path maze

Question

Given an odd integer N (5 <= N <= 51), generate a maze with side length N that follows the following requirements:

The maze must be composed of the characters | - and +. It must use the | character as a vertical wall, the - character as a horizontal wall, and if that wall turns, the character + should be used.

The width of the path must be one character.

The maze must turn at least four times.

The maze must have outer walls, that break at two points: the start and the end.

The maze must consist of one non-breaking path, from the start to the end.

For example, the following is a valid maze: (N = 5)

+---+
|   |
| | |
  |  
--+--

And for N = 7:

--+---+
  |   |
| | | |
| | | |
| | | |
|   |  
+---+--

Remember, this is code-golf, so the code with the fewest number of bytes wins.

Answer 1

Jelly, 36 35 34 33 32 bytes

2*×5H_2Bị⁾ |
_3”-ẋ”+;;Çsẋ2U3¦ṁµY

TryItOnline!

Builds a nighter™ the other way around to the examples like:

+---- |
|     |
| ----+
|     |
+---- |
|     |
| ----+

How?

2*×5H_2Bị⁾ | - Link 1, pipes & spaces: n      e.g. 7
2*           - 2 raised to the nth power      e.g. 128
  ×5         - multiply by 5                  e.g. 640
    H        - halve                          e.g. 320
     _2      - subtract 2                     e.g. 318
       B     - convert to binary              e.g. [1,0,0,1,1,1,1,1,0]
        ị    - index into (1-based)
         ⁾ | - char list " |"                 e.g. " ||     |"

_3”-ẋ”+;;Çsẋ2U3¦ṁµY - Main link: n            e.g. 7
_3                  - n - 3                   e.g. 4
  ”-                - char list "-"
    ẋ               - repeat                  e.g. "----"
     ”+             - char list "+"
       ;            - concatenate             e.g. "+----"
         Ç          - call last link (1) as a monad
        ;           - concatenate             e.g. "+---- ||     |"" 
          s         - split into chunks of n  e.g. ["+---- |","|     |"]
           ẋ2       - repeat 2 times          e.g. ["+---- |",
                                                    "|     |",
                                              +-->  "+---- |",
                                              |     "|     |"]
              3¦    - apply to index 3:       |
             U      -    upend                +---  "| ----+"
                ṁ   - mould like n (i.e. repeat to fill)
                 µ  - monadic chain separation
                  Y - join with line feeds

(each byte saved involved fairly non-trivial changes, see the edit history if you're interested, although I just noticed that Link 1 is the same byte count as the more conventional repeat and join: _2⁶ẋ“ ||“|”j)

Answer 2

JavaScript (ES6), 86 92 116

Almost a kolmogorv-complexity challenge ... With a little lateral thinking (inspired by @Neil's answer), it can be very shorter. Just turn 90°

n=>`|${s=' '[r='repeat'](n-2)}|
| ${h='-'[r](n-3)}+
|${s}|
+${h} |
`[r](n).slice(n*~n)

Test

f=
n=>`|${s=' '[r='repeat'](n-2)}|
| ${h='-'[r](n-3)}+
|${s}|
+${h} |
`[r](n).slice(n*~n)

function update() {
  var i=+I.value
  O.textContent=i&1? f(i): 'even'
}

update()

<input id=I value=7 min=5 max=49 step=2 type=number oninput="update()"><pre id=O><pre>

Answer 3

Batch, 216 bytes

@echo off
set s=
for /l %%i in (4,1,%1)do call set s=-%%s%%
set b= %s:-= %
set r=! %s%+
set s=+%s% !
call:e
for /l %%i in (5,2,%1)do call:l
:l
echo ^|%b%^|
set t=%s%
set s=%r%
set r=%t%
:e
echo %s:!=^|%

|s are awkward in Batch so I reflected rotated the examples instead.

Answer 4

PHP, 99 Bytes

up to down gates

for($s=str_pad("\n| ",$c=$argv[1],"-")."+\n";$i++<$c;)echo$i%2?$s=strrev($s):str_pad("|",$c-1)."|";

PHP, 157 Bytes

left right gates

<?=($p=str_pad)($n="\n",$c=1+$argv[1],"+---").$p($n,$c-1,"|   ")." #|"[$c%4].str_repeat($p($n,$c,"| "),$c-5).$p($n,$c-1,"  | ")."|# "[$c%4].$p($n,$c,"--+-");

@Titus Thank you for minialize the bytes

Answer 5

JavaScript (ES6), 87 bytes

A recursive function. Outputs a few trailing spaces.

f=(n,w=n,s=' -'[n&1].repeat(w-3),c='|+'[n&1])=>n?`
`+(n&2?c+s+' |':'| '+s+c)+f(n-1,w):s

Test

f=(n,w=n,s=' -'[n&1].repeat(w-3),c='|+'[n&1])=>n?`
`+(n&2?c+s+' |':'| '+s+c)+f(n-1,w):s

console.log(f(9));

Answer 6

Ruby 72 or 69 bytes

Lambda function. As shown, returns a newline-separated string. Delete the *$/ to return an array of strings.

->n{(1..n).map{|i|"|%s |+%s || %s|| %s+"[i%4*5,5]%(" -"[i%2]*(n-3))}*$/}

Draws a maze rotated 90 degrees from the examples. For each line, a format string is selected (for example +%s | for the 1st line (there is no zeroth line) and the %s is substituted with an appopriate number of - or spaces using the % operator (equivalent to sprintf, but shorter.)

Answer 7

Java 7, 228 bytes

String c(int n){String a="+x |",b="|y|\n",x,y,r=x=y="";int i=0;for(;i++<n-2;){x+=i>1?"-":"";y+=" ";}a=a.replace("x",x);b=b.replace("y",y);for(i=0;i<n;i++)r+=i%4<1?a+"\n":(i-2)%4==0?new StringBuffer(a).reverse()+"\n":b;return r;}

Used a similar vertical output as @JonathanAllan's Jelly answer.

Ungolfed & test code:

Try it here.

class M{
  static String c(int n){
    String a = "+x |",
           b = "|y|\n",
           x = "",
           y = "",
           r = "";
    int i = 0;
    for (; i++ < n-2;){
      x += i > 1
            ? "-"
            : "";
      y += " ";
    }
    a = a.replace("x", x);
    b = b.replace("y", y);
    for(i = 0; i < n; i++){
      r += i % 4 < 1
            ? a+"\n"
            : (i-2) % 4 == 0
               ? new StringBuffer(a).reverse()+"\n"
               : b;
    }
    return r;
  }

  public static void main(String[] a){
    System.out.println(c(7));
    System.out.println();
    System.out.println(c(25));
  }
}

Output:

+---- |
|     |
| ----+
|     |
+---- |
|     |
| ----+


+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |
|                       |
| ----------------------+
|                       |
+---------------------- |

Answer 8

Python 2, 89 bytes

def f(n):x='+'+'-'*(n-3)+' |';y='|'+' '*(n-2)+'|';print'\n'.join(([x,y,x[::-1],y]*n)[:n])

repl.it

Builds an internal wall, x, like '+---- |' and an internal corridor, y, like '| |'
Then builds a list of [x,y,x[::-1],y] (x[::-1] is a reverse of x)
Then repeats that list n times (as a single list), with *n, and truncates it to the first n entries, with (...)[:n], joins the list with line feeds, with '\n'.join(...), and prints the result.

Answer 9

Racket 187 bytes

Using display pattern by @JonathanAllan

(let*((u "+---- |")(v "|     |")(sr(λ(s)(list->string(reverse(string->list s)))))(g #t)(d displayln)
(p(λ()(d(if g u(sr u)))(set! g(if g #f #t)))))(for((i(ceiling(/ n 2))))(p)(d v))(p))

Ungolfed:

(define (f n)
  (let* ((sr (lambda(s)
               (list->string
                (reverse
                 (string->list s)))))
         (u "+---- |")
         (v "|     |")
         (g #t)
         (d displayln)
         (p (lambda()
              (d (if g u (sr u)))
              (set! g (if g #f #t)))))
    (for ((i (ceiling (/ n 2))))
      (p)
      (d v))
    (p)))

Testing:

(f 10)

Output:

+---- |
|     |
| ----+
|     |
+---- |
|     |
| ----+
|     |
+---- |
|     |
| ----+

Answer 10

T-SQL, 123/79 bytes

Golfed:

DECLARE @i INT=7

,@ INT=0z:PRINT
STUFF(CHOOSE(@%4+1,'+- |','|  |','| -+','|  |'),3,0,REPLICATE(IIF(@%2=0,'-',' '),@i))SET
@+=1IF @<@i GOTO z

Ungolfed:

DECLARE @i INT = 9

DECLARE @i INT=7

,@ INT=0
z:
  PRINT 
    STUFF(CHOOSE(@%4+1,'+- |','|  |','| -+','|  |'),3,0,
      REPLICATE(IIF(@%2=0,'-',' '),@i))
  SET @+=1
IF @<@i GOTO z

If you cheat and only make a narrow labyrinth the script can be golfed down to 79 bytes:

Golfed:

DECLARE @i INT = 9

,@ INT=0z:PRINT CHOOSE(@%4+1,'+- |','|  |','| -+','|  |')SET @+=1IF @<@i GOTO z

Ungolfed:

DECLARE @i INT = 9

,@ INT=0
z:
  PRINT CHOOSE(@%4+1,'+- |','|  |','| -+','|  |')
  SET @+=1
IF @<@i GOTO z

Fiddle for the long answer

Answer 11

GNU sed 140 bytes

Includes +1 for -r

s/1{5}//
h
s/^/+---+\n|   |\n| | |\n  |  \n--+--/
/1/!b
:w
s/^..(..)[^$]*/\1&/gm
s/11//
/1/bw
G
:h
s/\n[^\n]*\n([^\n]*\n)/&\1/
s/1//
/1/bh

Try it Online!

Takes input in unary (see this consensus).

Basically it inserts the size 5 maze, then appends the 2nd and 3rd character of each line to the beginning as many times as needed. Then duplicates the 3rd line (alternating | and ) as many times as needed.

The only interesting thing that I used is the m option on line 6 which allows ^ and $ to match respectively (in addition to the normal behavior) the empty string after a newline, and the empty string before a newline.

Answer 12

JavaScript (ES6), 96 bytes

f=(n,w=n-3)=>(h="-".repeat(w),n&2?`+${h} |`:`| ${h}+`)+(n>1?`
| ${" ".repeat(w)}|
`+f(n-2,w):"")

I was hoping recursion would turn out to be the shortest route, and apparently it is...