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Permutations (view source)

Revision as of 21:10, 13 November 2018

122 bytes added ,  5 years ago
m
→‎{{header|R}}
(→‎{{header|Haskell}}: Slight simplification, dropping a redundant import)
Line 5,401:
 
=={{header|R}}==
===Iterative version===
<lang r>next.perm <- function(p) {
<lang nr>next.perm <- lengthfunction(pa) {
in <- n - 1length(a)
ri =<- Tn
forwhile (i in> seq(n1 && a[i - 1,] 1)>= a[i]) {i <- i - 1
if (p[i] < p[i +== 1]) {
r = FNULL
} else break{
j <- ni▼
k <- n▼
while (j < k) {▼
x s <- pa[j]▼
p a[j] <- pa[k]▼
p a[k] <- xs▼
j <- j + 1▼
k <- k - 1▼
}
j s <- a[i +- 1]▼
p[ j] <- xi▼
while (pa[j] ><= p[i]s) j <- j -+ 1▼
p a[i - 1] <- pa[j]▼
a[j] <- j + 1s▼
# 1 2 3 a▼
}
▲ j <- i + 1
▲ k <- n
▲ while (j < k) {
▲ x <- p[j]
▲ p[j] <- p[k]
▲ p[k] <- x
▲ j <- j + 1
▲ k <- k - 1
}
if(r) return(NULL)
▲ j <- n
▲ while (p[j] > p[i]) j <- j - 1
▲ j <- j + 1
x <- p[i]▼
▲ p[i] <- p[j]
▲ p[j] <- x
return(p)
}
 
print.permsperm <- function(n) {
pe <- 1:nNULL
▲ xa <- p[i]1:n
while (!is.null(p)) {▼
repeat {
cat(p, "\n")
pe <- next.permcbind(pe, a)
a <- next.perm(a)
▲ while if (!is.null(pa)) {break
}
unname(e)
}
# 3 2 1}</lang>▼
 
'''Example'''
print.perms(3)
▲# 1 2 3
# 1 3 2
# 2 1 3
# 2 3 1
# 3 1 2
▲# 3 2 1</lang>
 
<lang>> perm(3)
Here is another recursive version.
[,1] [,2] [,3] [,4] [,5] [,6]
[1,] 1 1 2 2 3 3
[2,] 2 3 1 3 1 2
[3,] 3 2 3 1 2 1</lang>
 
===Recursive version===
<lang r># list of the vectors by inserting x in s at position 0...end.
linsert <- function(x,s) lapply(0:length(s), function(k) append(s,x,k))
Eoraptor
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