Combinations with repetitions: Difference between revisions
→Concise recursive: Changed to Wren S/H
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cwr( 3, 2)= 6
cwr(10, 3)= 220
</pre>
=={{header|Acornsoft Lisp}}==
{{trans|Scheme}}
<syntaxhighlight lang="lisp">
(defun samples (k items)
(cond
((zerop k) '(()))
((null items) '())
(t (append
(mapc '(lambda (c) (cons (car items) c))
(samples (sub1 k) items))
(samples k (cdr items))))))
(defun append (a b)
(cond ((null a) b)
(t (cons (car a) (append (cdr a) b)))))
(defun length (list (len . 0))
(map '(lambda (e) (setq len (add1 len)))
list)
len)
</syntaxhighlight>
{{Out}}
<pre>
Evaluate : (samples 2 '(iced jam plain))
Value is : ((iced iced) (iced jam) (iced plain) (jam jam)
(jam plain) (plain plain))
Evaluate : (length (samples 3 '(1 2 3 4 5 6 7 8 9 10)))
Value is : 220
</pre>
Line 1,190 ⟶ 1,226:
<syntaxhighlight lang="text">
items$[] = [ "iced" "jam" "plain" ]
n = len items$[]
k = 2
len result[] k
n_results = 0
#
proc output . .
n_results += 1
if len items$[] > 0
s$ = ""
for i = 1 to k
s$ &= items$[result[i]] & " "
.
print s$
.
.
proc combine pos val . .
if pos > k
else
for i = val to n
result[pos] = i
.
.
.
#
n = 10
Line 1,207 ⟶ 1,259:
items$[] = [ ]
n_results = 0
print ""
print n_results & " results with 10 donuts"
Line 2,735 ⟶ 2,787:
{{out}}
<pre>
220
</pre>
As of 1.0.2 there is a builtin combinations_with_repetitions() function. Using a string here for simplicity and neater output, but it works with any sequence:
<!--<syntaxhighlight lang="phix">(phixonline)-->
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">join</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">combinations_with_repetitions</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"ijp"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">),</span><span style="color: #008000;">','</span><span style="color: #0000FF;">)</span>
<span style="color: #0000FF;">?</span><span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">combinations_with_repetitions</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">10</span><span style="color: #0000FF;">),</span><span style="color: #000000;">3</span><span style="color: #0000FF;">))</span>
<!--</syntaxhighlight>-->
{{out}}
<pre>
"ii,ij,ip,jj,jp,pp"
220
</pre>
Line 3,975 ⟶ 4,037:
{{trans|Go}}
Produces results in no particular order.
<syntaxhighlight lang="
if (n == 0 ) return [[]]
if (lst.count == 0) return []
var r =
for (x in
var y = x.toList
y.add(lst[0])
Line 3,988 ⟶ 4,049:
}
System.print(
System.print(
{{out}}
Line 3,996 ⟶ 4,057:
220
</pre>
===Library based===
{{libheader|Wren-seq}}
{{libheader|Wren-perm}}
Produces results in lexicographic order.
<syntaxhighlight lang="
import "./perm" for Comb
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