Optimal Alphabet Stepping











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Given an input string consisting of only letters, return the step-size that results in the minimum amount of steps that are needed to visit all the letters in order over a wrapping alphabet, starting at any letter.



For example, take the word, dog. If we use a step-size of 1, we end up with:



defghijklmnopqrstuvwxyzabcdefg   Alphabet
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
defghijklmnopqrstuvwxyzabcdefg Visited letters
d o g Needed letters


For a total of 30 steps.



However, if we use a step-size of 11, we get:



defghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg
^ ^ ^ ^ ^ ^
d o z k v g Visited letters
d o g Needed letters


For a total of 6 steps. This is the minimum amount of steps, so the return result for dog is the step-size; 11.



Test cases:



"dog"      -> 11
"age" -> 6
"apple" -> 19
"alphabet" -> 9
"aaaaaaa" -> 0 for 0 indexed, 26 for 1 indexed
"abcdefga" -> 1 or 9
"aba" -> Any odd number except for 13
"ppcg" -> 15
"codegolf" -> 15
"testcase" -> 9
"z" -> Any number
"joking" -> 19


Rules




  • Input will be a non-empty string consisting only of the letters a to z (you can choose between uppercase or lowercase)

  • Output can be 0 indexed (i.e. the range 0-25) or 1 indexed (1-26)

  • If there's a tie, you can output any step-size or all of them

  • This is code-golf, so the lowest amount of bytes for each language wins!










share|improve this question
























  • Do we need to handle empty input?
    – pizzapants184
    2 hours ago






  • 1




    @pizzapants184 No. I've updated the question to specify the input will be non-empty
    – Jo King
    2 hours ago








  • 1




    @pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
    – Jo King
    1 hour ago










  • Can we take input as an array of characters?
    – Shaggy
    8 mins ago















up vote
6
down vote

favorite
1












Given an input string consisting of only letters, return the step-size that results in the minimum amount of steps that are needed to visit all the letters in order over a wrapping alphabet, starting at any letter.



For example, take the word, dog. If we use a step-size of 1, we end up with:



defghijklmnopqrstuvwxyzabcdefg   Alphabet
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
defghijklmnopqrstuvwxyzabcdefg Visited letters
d o g Needed letters


For a total of 30 steps.



However, if we use a step-size of 11, we get:



defghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg
^ ^ ^ ^ ^ ^
d o z k v g Visited letters
d o g Needed letters


For a total of 6 steps. This is the minimum amount of steps, so the return result for dog is the step-size; 11.



Test cases:



"dog"      -> 11
"age" -> 6
"apple" -> 19
"alphabet" -> 9
"aaaaaaa" -> 0 for 0 indexed, 26 for 1 indexed
"abcdefga" -> 1 or 9
"aba" -> Any odd number except for 13
"ppcg" -> 15
"codegolf" -> 15
"testcase" -> 9
"z" -> Any number
"joking" -> 19


Rules




  • Input will be a non-empty string consisting only of the letters a to z (you can choose between uppercase or lowercase)

  • Output can be 0 indexed (i.e. the range 0-25) or 1 indexed (1-26)

  • If there's a tie, you can output any step-size or all of them

  • This is code-golf, so the lowest amount of bytes for each language wins!










share|improve this question
























  • Do we need to handle empty input?
    – pizzapants184
    2 hours ago






  • 1




    @pizzapants184 No. I've updated the question to specify the input will be non-empty
    – Jo King
    2 hours ago








  • 1




    @pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
    – Jo King
    1 hour ago










  • Can we take input as an array of characters?
    – Shaggy
    8 mins ago













up vote
6
down vote

favorite
1









up vote
6
down vote

favorite
1






1





Given an input string consisting of only letters, return the step-size that results in the minimum amount of steps that are needed to visit all the letters in order over a wrapping alphabet, starting at any letter.



For example, take the word, dog. If we use a step-size of 1, we end up with:



defghijklmnopqrstuvwxyzabcdefg   Alphabet
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
defghijklmnopqrstuvwxyzabcdefg Visited letters
d o g Needed letters


For a total of 30 steps.



However, if we use a step-size of 11, we get:



defghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg
^ ^ ^ ^ ^ ^
d o z k v g Visited letters
d o g Needed letters


For a total of 6 steps. This is the minimum amount of steps, so the return result for dog is the step-size; 11.



Test cases:



"dog"      -> 11
"age" -> 6
"apple" -> 19
"alphabet" -> 9
"aaaaaaa" -> 0 for 0 indexed, 26 for 1 indexed
"abcdefga" -> 1 or 9
"aba" -> Any odd number except for 13
"ppcg" -> 15
"codegolf" -> 15
"testcase" -> 9
"z" -> Any number
"joking" -> 19


Rules




  • Input will be a non-empty string consisting only of the letters a to z (you can choose between uppercase or lowercase)

  • Output can be 0 indexed (i.e. the range 0-25) or 1 indexed (1-26)

  • If there's a tie, you can output any step-size or all of them

  • This is code-golf, so the lowest amount of bytes for each language wins!










share|improve this question















Given an input string consisting of only letters, return the step-size that results in the minimum amount of steps that are needed to visit all the letters in order over a wrapping alphabet, starting at any letter.



For example, take the word, dog. If we use a step-size of 1, we end up with:



defghijklmnopqrstuvwxyzabcdefg   Alphabet
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
defghijklmnopqrstuvwxyzabcdefg Visited letters
d o g Needed letters


For a total of 30 steps.



However, if we use a step-size of 11, we get:



defghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefg
^ ^ ^ ^ ^ ^
d o z k v g Visited letters
d o g Needed letters


For a total of 6 steps. This is the minimum amount of steps, so the return result for dog is the step-size; 11.



Test cases:



"dog"      -> 11
"age" -> 6
"apple" -> 19
"alphabet" -> 9
"aaaaaaa" -> 0 for 0 indexed, 26 for 1 indexed
"abcdefga" -> 1 or 9
"aba" -> Any odd number except for 13
"ppcg" -> 15
"codegolf" -> 15
"testcase" -> 9
"z" -> Any number
"joking" -> 19


Rules




  • Input will be a non-empty string consisting only of the letters a to z (you can choose between uppercase or lowercase)

  • Output can be 0 indexed (i.e. the range 0-25) or 1 indexed (1-26)

  • If there's a tie, you can output any step-size or all of them

  • This is code-golf, so the lowest amount of bytes for each language wins!







code-golf alphabet






share|improve this question















share|improve this question













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share|improve this question








edited 1 hour ago

























asked 3 hours ago









Jo King

20.2k245106




20.2k245106












  • Do we need to handle empty input?
    – pizzapants184
    2 hours ago






  • 1




    @pizzapants184 No. I've updated the question to specify the input will be non-empty
    – Jo King
    2 hours ago








  • 1




    @pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
    – Jo King
    1 hour ago










  • Can we take input as an array of characters?
    – Shaggy
    8 mins ago


















  • Do we need to handle empty input?
    – pizzapants184
    2 hours ago






  • 1




    @pizzapants184 No. I've updated the question to specify the input will be non-empty
    – Jo King
    2 hours ago








  • 1




    @pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
    – Jo King
    1 hour ago










  • Can we take input as an array of characters?
    – Shaggy
    8 mins ago
















Do we need to handle empty input?
– pizzapants184
2 hours ago




Do we need to handle empty input?
– pizzapants184
2 hours ago




1




1




@pizzapants184 No. I've updated the question to specify the input will be non-empty
– Jo King
2 hours ago






@pizzapants184 No. I've updated the question to specify the input will be non-empty
– Jo King
2 hours ago






1




1




@pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
– Jo King
1 hour ago




@pizzapants184 Thanks, updating the question. Please let me know if any more of my test cases are wrong. I think that was left over from a previous iteration of the question
– Jo King
1 hour ago












Can we take input as an array of characters?
– Shaggy
8 mins ago




Can we take input as an array of characters?
– Shaggy
8 mins ago










2 Answers
2






active

oldest

votes

















up vote
1
down vote














Python 2, 222 bytes





A=map(chr,range(65,91))
def t(s,l,S=0):
a=i=A.index(s[0])
for c in s[1:]:
while a!=A.index(c):
S+=1;a+=l;a%=26
if a==i:return float('inf')
i=a
return S
def f(s):T=[t(s,l)for l in range(26)];return T.index(min(T))


Try it online!



-8 bytes from Jo King



This would be shorter in a language with a prime number of letters (wouldn't need the float('inf') handling of infinite loops). Actually, this submission would still need that for handling strings like "aaa".



This submission is 0-indexed (returns values from 0 to 25 inclusive).



f takes a(n uppercase) string and returns the Optimal Alphabet Stepping



t is a helper function that takes the string and an alphabet stepping and returns the number of hops needed to finish the string (or float('inf') if impossible).






share|improve this answer



















  • 1




    216 bytes
    – Jo King
    1 hour ago












  • Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
    – tsh
    22 mins ago




















up vote
1
down vote













JavaScript, 153 bytes





w=>[...Array(26)].map((_,i)=>i).map((_,s,a)=>~[...w].map(c=>(t+=a.find(v=>!p|(u(c,36)+~v*s-u(p,36))%26==0),p=c),p=t=0,u=parseInt)+t<m&&(m=t,n=s),m=1/0)|n


Try it online!






share|improve this answer





















  • 144 bytes
    – Shaggy
    7 mins ago











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2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
1
down vote














Python 2, 222 bytes





A=map(chr,range(65,91))
def t(s,l,S=0):
a=i=A.index(s[0])
for c in s[1:]:
while a!=A.index(c):
S+=1;a+=l;a%=26
if a==i:return float('inf')
i=a
return S
def f(s):T=[t(s,l)for l in range(26)];return T.index(min(T))


Try it online!



-8 bytes from Jo King



This would be shorter in a language with a prime number of letters (wouldn't need the float('inf') handling of infinite loops). Actually, this submission would still need that for handling strings like "aaa".



This submission is 0-indexed (returns values from 0 to 25 inclusive).



f takes a(n uppercase) string and returns the Optimal Alphabet Stepping



t is a helper function that takes the string and an alphabet stepping and returns the number of hops needed to finish the string (or float('inf') if impossible).






share|improve this answer



















  • 1




    216 bytes
    – Jo King
    1 hour ago












  • Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
    – tsh
    22 mins ago

















up vote
1
down vote














Python 2, 222 bytes





A=map(chr,range(65,91))
def t(s,l,S=0):
a=i=A.index(s[0])
for c in s[1:]:
while a!=A.index(c):
S+=1;a+=l;a%=26
if a==i:return float('inf')
i=a
return S
def f(s):T=[t(s,l)for l in range(26)];return T.index(min(T))


Try it online!



-8 bytes from Jo King



This would be shorter in a language with a prime number of letters (wouldn't need the float('inf') handling of infinite loops). Actually, this submission would still need that for handling strings like "aaa".



This submission is 0-indexed (returns values from 0 to 25 inclusive).



f takes a(n uppercase) string and returns the Optimal Alphabet Stepping



t is a helper function that takes the string and an alphabet stepping and returns the number of hops needed to finish the string (or float('inf') if impossible).






share|improve this answer



















  • 1




    216 bytes
    – Jo King
    1 hour ago












  • Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
    – tsh
    22 mins ago















up vote
1
down vote










up vote
1
down vote










Python 2, 222 bytes





A=map(chr,range(65,91))
def t(s,l,S=0):
a=i=A.index(s[0])
for c in s[1:]:
while a!=A.index(c):
S+=1;a+=l;a%=26
if a==i:return float('inf')
i=a
return S
def f(s):T=[t(s,l)for l in range(26)];return T.index(min(T))


Try it online!



-8 bytes from Jo King



This would be shorter in a language with a prime number of letters (wouldn't need the float('inf') handling of infinite loops). Actually, this submission would still need that for handling strings like "aaa".



This submission is 0-indexed (returns values from 0 to 25 inclusive).



f takes a(n uppercase) string and returns the Optimal Alphabet Stepping



t is a helper function that takes the string and an alphabet stepping and returns the number of hops needed to finish the string (or float('inf') if impossible).






share|improve this answer















Python 2, 222 bytes





A=map(chr,range(65,91))
def t(s,l,S=0):
a=i=A.index(s[0])
for c in s[1:]:
while a!=A.index(c):
S+=1;a+=l;a%=26
if a==i:return float('inf')
i=a
return S
def f(s):T=[t(s,l)for l in range(26)];return T.index(min(T))


Try it online!



-8 bytes from Jo King



This would be shorter in a language with a prime number of letters (wouldn't need the float('inf') handling of infinite loops). Actually, this submission would still need that for handling strings like "aaa".



This submission is 0-indexed (returns values from 0 to 25 inclusive).



f takes a(n uppercase) string and returns the Optimal Alphabet Stepping



t is a helper function that takes the string and an alphabet stepping and returns the number of hops needed to finish the string (or float('inf') if impossible).







share|improve this answer














share|improve this answer



share|improve this answer








edited 58 mins ago

























answered 1 hour ago









pizzapants184

2,594716




2,594716








  • 1




    216 bytes
    – Jo King
    1 hour ago












  • Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
    – tsh
    22 mins ago
















  • 1




    216 bytes
    – Jo King
    1 hour ago












  • Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
    – tsh
    22 mins ago










1




1




216 bytes
– Jo King
1 hour ago






216 bytes
– Jo King
1 hour ago














Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
– tsh
22 mins ago






Use while a!=A(c)and S<len(s)*26: and you may remove if a==i:return float('inf'), since len(s)*26 is upper bound of any answer.
– tsh
22 mins ago












up vote
1
down vote













JavaScript, 153 bytes





w=>[...Array(26)].map((_,i)=>i).map((_,s,a)=>~[...w].map(c=>(t+=a.find(v=>!p|(u(c,36)+~v*s-u(p,36))%26==0),p=c),p=t=0,u=parseInt)+t<m&&(m=t,n=s),m=1/0)|n


Try it online!






share|improve this answer





















  • 144 bytes
    – Shaggy
    7 mins ago















up vote
1
down vote













JavaScript, 153 bytes





w=>[...Array(26)].map((_,i)=>i).map((_,s,a)=>~[...w].map(c=>(t+=a.find(v=>!p|(u(c,36)+~v*s-u(p,36))%26==0),p=c),p=t=0,u=parseInt)+t<m&&(m=t,n=s),m=1/0)|n


Try it online!






share|improve this answer





















  • 144 bytes
    – Shaggy
    7 mins ago













up vote
1
down vote










up vote
1
down vote









JavaScript, 153 bytes





w=>[...Array(26)].map((_,i)=>i).map((_,s,a)=>~[...w].map(c=>(t+=a.find(v=>!p|(u(c,36)+~v*s-u(p,36))%26==0),p=c),p=t=0,u=parseInt)+t<m&&(m=t,n=s),m=1/0)|n


Try it online!






share|improve this answer












JavaScript, 153 bytes





w=>[...Array(26)].map((_,i)=>i).map((_,s,a)=>~[...w].map(c=>(t+=a.find(v=>!p|(u(c,36)+~v*s-u(p,36))%26==0),p=c),p=t=0,u=parseInt)+t<m&&(m=t,n=s),m=1/0)|n


Try it online!







share|improve this answer












share|improve this answer



share|improve this answer










answered 37 mins ago









tsh

8,15511546




8,15511546












  • 144 bytes
    – Shaggy
    7 mins ago


















  • 144 bytes
    – Shaggy
    7 mins ago
















144 bytes
– Shaggy
7 mins ago




144 bytes
– Shaggy
7 mins ago


















draft saved

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