Swift permutations of the digits of an Integer
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?
swift
edited 14 mins ago
janos
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
add a comment |
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?
swift
edited 14 mins ago
janos
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
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
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 hours ago
add a comment |
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?
swift
edited 14 mins ago
janos
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
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
swift
edited 14 mins ago
janos
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
edited 14 mins ago
janos
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
edited 14 mins ago
janos
96.8k12124350
edited 14 mins ago
janos
96.8k12124350
edited 14 mins ago
janos
96.8k12124350
96.8k12124350
asked 7 hours ago
stevenpcurtis
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.
asked 7 hours ago
stevenpcurtis
1111
asked 7 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
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 hours ago
add a comment |
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
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 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
5 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
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 hours ago
add a comment |
1 Answer
1
active
oldest
votes
up vote
0
down vote
permsOfInteger uses math operations divide and module to convert an Int to an array. By contrast, perms converts digits to strings and joins them to convert an array to Int. I think it's good to be consistent, I would use math operations for converting in both directions. And I would extract these operations to helper methods intToDigits and digitsToInt.
answered 5 mins ago
janos
96.8k12124350
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
});
});
}, "mathjax-editing");
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "196"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
stevenpcurtis is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f209791%2fswift-permutations-of-the-digits-of-an-integer%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
permsOfInteger uses math operations divide and module to convert an Int to an array. By contrast, perms converts digits to strings and joins them to convert an array to Int. I think it's good to be consistent, I would use math operations for converting in both directions. And I would extract these operations to helper methods intToDigits and digitsToInt.
answered 5 mins ago
janos
96.8k12124350
add a comment |
up vote
0
down vote
permsOfInteger uses math operations divide and module to convert an Int to an array. By contrast, perms converts digits to strings and joins them to convert an array to Int. I think it's good to be consistent, I would use math operations for converting in both directions. And I would extract these operations to helper methods intToDigits and digitsToInt.
answered 5 mins ago
janos
96.8k12124350
add a comment |
up vote
0
down vote
up vote
0
down vote
permsOfInteger uses math operations divide and module to convert an Int to an array. By contrast, perms converts digits to strings and joins them to convert an array to Int. I think it's good to be consistent, I would use math operations for converting in both directions. And I would extract these operations to helper methods intToDigits and digitsToInt.
answered 5 mins ago
janos
96.8k12124350
permsOfInteger uses math operations divide and module to convert an Int to an array. By contrast, perms converts digits to strings and joins them to convert an array to Int. I think it's good to be consistent, I would use math operations for converting in both directions. And I would extract these operations to helper methods intToDigits and digitsToInt.
answered 5 mins ago
janos
96.8k12124350
answered 5 mins ago
janos
96.8k12124350
answered 5 mins ago
janos
96.8k12124350
answered 5 mins ago
janos
96.8k12124350
96.8k12124350
add a comment |
add a comment |
stevenpcurtis is a new contributor. Be nice, and check out our Code of Conduct.
stevenpcurtis is a new contributor. Be nice, and check out our Code of Conduct.
stevenpcurtis is a new contributor. Be nice, and check out our Code of Conduct.
stevenpcurtis is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Code Review Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fcodereview.stackexchange.com%2fquestions%2f209791%2fswift-permutations-of-the-digits-of-an-integer%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
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
5 hours ago
Exactly. That is correct.
– stevenpcurtis
5 hours ago