Build a simple room in ASCII-art

Question

A room can be made up of connected rectangles, for instance an L-shaped room. Such a room can be described by a list of dimensions describing the size of each rectangle.

Assume you have two input lists. The first contains the width of rectangles stacked vertically over each other. The second contains the height of the rectangles.

As an example, the input [4 6][3 2] will be a 4-by-3 rectangle on top of a 6-by-2 rectangle. The figure below shows this shape. Note that the walls are considered "thin", thus it's the spaces between the wall that's determined by the input.

[4 6][3 2]
 ____
|    |
|    |
|    |_
|      |
|______|

The challenge is: Take a list of dimensions as input, and output the shape of the room as ASCII-art. The format must be as in the sample figures:

• All horizontal walls are shown using underscores
• All vertical walls are shown using bars
• There shall be no walls where the rectangles are connected
• The left wall is straight
• For more details, have a look at the test cases

Assumptions you can make:

• All dimensions are in the range [1 ... 20]
  • All horizonal dimensions are even numbers
• The number of rectangles will be in the range [1 ... 10]
• Only valid input is given
• Optional input format (you can decide the order of the input dimensions, please specify in the answer).

Test cases:

[2][1]
 __
|__|

---

[4][2]
 ____
|    |
|____|

---

[2 6 2 4][2 2 1 3]
 __
|  |
|  |___
|      |
|   ___|
|  |_
|    |
|    |
|____|

---

[2 14 6 8 4 18 2 10 4 2][1 2 3 1 2 1 1 1 2 1]
 __
|  |___________
|              |
|       _______|
|      |
|      |
|      |_
|     ___|
|    |
|    |_____________
|   _______________|
|  |______
|     ____|
|    |
|   _|
|__|

Answer 1

JavaScript (ES6) 174

The only critical part is the horizontal row joining 2 parts of different widths, with the vertical bar on right side that can be in the middle or at the right end.

(p,h,q=-1,R=(n,s=' ')=>s.repeat(n))=>[...p,0].map((x,i)=>(x>q?p=x:(p=q,q=x),(~q?`
|`+R(q+(x<p)-!x)+R(x>q,'|'):' ')+R(p+~q+!x,'_')+R(x<p,'|')+R(h[i]-1,`
|${R(q=x)}|`))).join``

TEST

f=(p,h,q=-1,R=(n,s=' ')=>s.repeat(n))=>[...p,0].map((x,i)=>(x>q?p=x:(p=q,q=x),(~q?`
|`+R(q+(x<p)-!x)+R(x>q,'|'):' ')+R(p+~q+!x,'_')+R(x<p,'|')+R(h[i]-1,`
|${R(q=x)}|`))).join``

// Less golfed

F=(p,h, q=-1, 
   R=(n,s=' ')=>s.repeat(n)
  )=>
  [...p, 0].map((x,i)=> (
    x>q? p=x : (p=q,q=x),
    (q>=0?`\n|`+R(q+(x<p)-!x)+R(x>q,'|'):' ')
    + R(p+~q+!x,'_') + R(x<p,'|')
    + R(h[i]-1,`\n|${R(q=x)}|`)
  )).join``

console.log=x=>O.textContent+=x+'\n'

;[  
  [[2],[1]],
  [[4],[2]],
  [[2, 6, 2, 4],[2, 2, 1, 3]],
  [[2, 14, 6, 8, 4, 18, 2, 10, 4, 2],[1, 2, 3, 1, 2, 1, 1, 1, 2, 1]]
].forEach(t=>{
  var w=t[0],h=t[1]
  console.log('['+w+'] ['+h+']\n'+f(w,h)+'\n')
})

<pre id=O></pre>

Answer 2

Python 3, 230 223 222 217 bytes

def f(a):b=a[0]+[0];m=' _';print('\n'.join([' '+'_'*b[0]+' ']+['|'+' '*min(b[l],b[l+1])+m[b[l+1]<1]*(b[l]>b[l+1])+m[k]*(b[l]-b[l+1]-1)+'|'+m[k]*(b[l+1]-b[l]-1)for l,i in enumerate(zip(*a))for k in[0]*(i[1]-1)+[1]]))

Thanks to @StewieGriffin @KevinLau for their help

Results

>>> f([[2, 14, 6, 8, 4, 18, 2, 10, 4, 2],[1, 2, 3, 1, 2, 1, 1, 1, 2, 1]])
 __ 
|  |___________
|              |
|       _______|
|      | 
|      | 
|      |_
|     ___|
|    |             
|    |_____________
|   _______________|
|  |_______
|     _____|
|    |
|   _|
|__|

Answer 3

Ruby 191

First time golfing, also it's my first day with Ruby, so it's probably not the most elegant thing in the world, but it'll do?

def f(x)
a=x[0]+[0]
puts" #{'_'*a[0]} "
for i in 0..x[1].length-1
n,m=a[i,2].sort
puts"|#{' '*a[i]}|\n"*(x[1][i]-1)+'|'+' '*n+(a[i+1]<1?'_':m>a[i]?'|':' ')+'_'*(m-n-1)+(n<a[i]?'|':'')
end
end

Answer 4

Retina, 169 150 113 bytes

Byte count assumes ISO 8859-1 encoding.

\d+
$*
{+r`1(1*¶[^|]*(1+))
$1¶|$2|
}` (¶.*) 1+
$1
1
_
(\|_+)\|(?=¶\1_(_+))
$1|$2
T`w` `(\|_+)_?(?=_*\|.*¶\1)
^¶
 

The code contains a trailing space on a trailing newline.

Input format:

Height (separated by spaces)
Width (also separated by spaces)

For example:

1 2 3 1 2 1 1 1 2 1
2 14 6 8 4 18 2 10 4 2

Try it online!