Input  : [5,5,5,5,5] 100
Output : 5*5*5-5*5

Input  : [1,2,3,4,5] 0
Output : 12-3-4-5

fqeQvTms.ihQd^"+-*/"lth

DECLARE @ varchar(max)= '5,5,5'
DECLARE @a varchar(20) = '125'

,@ varchar(max)='';WITH D as(SELECT @a a UNION ALL SELECT STUFF(a,charindex(',',a),1,value)FROM STRING_SPLIT('*,+,./,-,',',')x,d WHERE a like'%,%')SELECT @+=a+','''+REPLACE(a,'.','')+'''),('FROM D WHERE a not like'%,%'EXEC('SELECT y FROM(values('+@+'null,null))g(x,y)WHERE x='+@b)

DECLARE @a varchar(max)= '5,5,5'
DECLARE @b varchar(20) = '5'

,@ varchar(max)=''
;WITH D as
(
  SELECT @a a
  UNION ALL
  SELECT STUFF(a,charindex(',',a),1,value)
  FROM STRING_SPLIT('*,+,./,-,',',')x,d
  WHERE a like'%,%'
)
SELECT @+=a+','''+REPLACE(a,',','')+'''),('
FROM D
WHERE a not like'%,%'

EXEC('SELECT y FROM(values('+@+'null,null))g(x,y)WHERE x='+@b)

a=>o=>(c=[],i=c=>{for(j=0;!((c[j]?++c[j]:c[j]=1)%5);)c[j++]=0},eval(`while(eval(e=(a+'').replace(/,/g,(_,j)=>'+-*/'.charAt(c[~-j/2])))!=o)i(c);e`))

n=length(x)-1
k=n*2+2
p=unique(nchoosek(repmat('*-+/',1,n),n),'rows')
p=[p char(' '*~~p(:,1))]'
c=char(x'*~~p(1,:))
o=p(:,r==cellfun(@eval,mat2cell(reshape([c(:) p(:)]',k,[]),k,0|p(1,:))))
reshape([repmat(x',size(o,2),1) o(:)]',k,[])'

1*2*3+4+5
1+2+3+4+5
1-2*3+4*5

n=length(x)-1;
p=unique(nchoosek(repmat(['*','-','+','/'],1,n),n),'rows');
l=length(p);
p=[p repmat(' ',l,1)]';
c=reshape([repmat(x',l,1) p(:)]',n*2+2,[]);
o = p(:,r == cellfun(@eval, mat2cell(c,n*2+2,ones(l,1))));
reshape([repmat(x',size(o,2),1) o(:)]',n*2+2,[])'

from itertools import*
def f(n,o):print({k for k in[''.join(map(str,sum(j,())))[1:]for j in[zip(x,n)for x in product('+-*/',repeat=len(n))]]if eval(k)==o})

def x(i,r):
 t=""
 from random import choice as c
 while True:
  for j in i:
   t+=str(j)
   if c([0,1]):t+="."+c("+-/*")
  t=t.strip("+-*/.")+"."
  v=eval(t)
  if v == r:print t
  t=""

a=>o=>eval(`while(eval(e=(a+'').replace(/,/g,_=>'+-*/'.charAt(Math.random()*5)))!=o);e`)