Swift permutations of the digits of an Integer











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2
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I want to return all of the permutations of an integer in Swift.



var outputArray = [[Int]]()
func perms ( _ input: [Int], _ output: [Int]) {
if input.count == 0 {
outputArray.append( [ Int( output.map{ String($0) }.joined() )! ] )
}
else {
for i in 0..<input.count {
let current = [input[i]]
let before = Array( input [0..<i] )
let after = Array( input [(i + 1) ..< input.count] )
perms(before + after, current + output)
}
}
}

func permsOfInteger(_ input: Int) -> [[Int]] {
var inp = input
var inpArray = [Int]()
while inp > 0 {
inpArray.append(inp % 10)
inp = inp / 10
}
perms(inpArray, )
return (outputArray)
}


( permsOfInteger(5432) )



I don't want to switch the algorithm (I'm aware of Heap's algorithm) but rather improve my implementation here. Any advice?










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  • 1




    Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
    – user1118321
    4 hours ago










  • Exactly. That is correct.
    – stevenpcurtis
    4 hours ago















up vote
2
down vote

favorite












I want to return all of the permutations of an integer in Swift.



var outputArray = [[Int]]()
func perms ( _ input: [Int], _ output: [Int]) {
if input.count == 0 {
outputArray.append( [ Int( output.map{ String($0) }.joined() )! ] )
}
else {
for i in 0..<input.count {
let current = [input[i]]
let before = Array( input [0..<i] )
let after = Array( input [(i + 1) ..< input.count] )
perms(before + after, current + output)
}
}
}

func permsOfInteger(_ input: Int) -> [[Int]] {
var inp = input
var inpArray = [Int]()
while inp > 0 {
inpArray.append(inp % 10)
inp = inp / 10
}
perms(inpArray, )
return (outputArray)
}


( permsOfInteger(5432) )



I don't want to switch the algorithm (I'm aware of Heap's algorithm) but rather improve my implementation here. Any advice?










share|improve this question









New contributor




stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 1




    Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
    – user1118321
    4 hours ago










  • Exactly. That is correct.
    – stevenpcurtis
    4 hours ago













up vote
2
down vote

favorite









up vote
2
down vote

favorite











I want to return all of the permutations of an integer in Swift.



var outputArray = [[Int]]()
func perms ( _ input: [Int], _ output: [Int]) {
if input.count == 0 {
outputArray.append( [ Int( output.map{ String($0) }.joined() )! ] )
}
else {
for i in 0..<input.count {
let current = [input[i]]
let before = Array( input [0..<i] )
let after = Array( input [(i + 1) ..< input.count] )
perms(before + after, current + output)
}
}
}

func permsOfInteger(_ input: Int) -> [[Int]] {
var inp = input
var inpArray = [Int]()
while inp > 0 {
inpArray.append(inp % 10)
inp = inp / 10
}
perms(inpArray, )
return (outputArray)
}


( permsOfInteger(5432) )



I don't want to switch the algorithm (I'm aware of Heap's algorithm) but rather improve my implementation here. Any advice?










share|improve this question









New contributor




stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I want to return all of the permutations of an integer in Swift.



var outputArray = [[Int]]()
func perms ( _ input: [Int], _ output: [Int]) {
if input.count == 0 {
outputArray.append( [ Int( output.map{ String($0) }.joined() )! ] )
}
else {
for i in 0..<input.count {
let current = [input[i]]
let before = Array( input [0..<i] )
let after = Array( input [(i + 1) ..< input.count] )
perms(before + after, current + output)
}
}
}

func permsOfInteger(_ input: Int) -> [[Int]] {
var inp = input
var inpArray = [Int]()
while inp > 0 {
inpArray.append(inp % 10)
inp = inp / 10
}
perms(inpArray, )
return (outputArray)
}


( permsOfInteger(5432) )



I don't want to switch the algorithm (I'm aware of Heap's algorithm) but rather improve my implementation here. Any advice?







swift






share|improve this question









New contributor




stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question









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stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









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edited 3 mins ago









janos

96.8k12124350




96.8k12124350






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asked 6 hours ago









stevenpcurtis

1111




1111




New contributor




stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






stevenpcurtis is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1




    Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
    – user1118321
    4 hours ago










  • Exactly. That is correct.
    – stevenpcurtis
    4 hours ago














  • 1




    Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
    – user1118321
    4 hours ago










  • Exactly. That is correct.
    – stevenpcurtis
    4 hours ago








1




1




Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
– user1118321
4 hours ago




Just a quick clarification - can you elaborate on what it means to permute an integer? Do you mean generate all the permutations of the numerals that make up the number? Like the number 123 would generate "123", "132", "213", "231", "312", "321"?
– user1118321
4 hours ago












Exactly. That is correct.
– stevenpcurtis
4 hours ago




Exactly. That is correct.
– stevenpcurtis
4 hours ago















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