1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
/*
def multichoose(k, objects):
"""n multichoose k multisets from the list of objects. n is the size of
the objects."""
j,j_1,q = k,k,k # init here for scoping
r = len(objects) - 1
a = [0 for i in range(k)] # initial multiset indexes
while True:
yield [objects[a[i]] for i in range(0,k)] # emit result
j = k - 1
while j >= 0 and a[j] == r: j -= 1
if j < 0: break # check for end condition
j_1 = j
while j_1 <= k - 1:
a[j_1] = a[j_1] + 1 # increment
q = j_1
while q < k - 1:
a[q+1] = a[q] # shift left
q += 1
q += 1
j_1 = q
*/
var range = require('range')
function multichoose(k, objects, cb) {
var j=k,j_1=k,q=k
var r = objects.length - 1
var a = range(0,k).map(function() { return 0 })
while (true) {
cb(range(0,k).map(function(i) { return objects[a[i]] }))
j = k - 1
while (j >= 0 && a[j] == r) --j
if (j < 0) break
j_1 = j
while (j_1 <= k - 1) {
a[j_1] = a[j_1] + 1
var q = j_1
while (q < k - 1) {
a[q+1] = a[q]
++q
}
++q
j_1 = q
}
}
}
module.exports = multichoose
|
