I am tasked to write a function that returns whether two strings are substitution ciphers of each other. It is assumed that one isn't given a key. The output is expected to return True or False.
Here is what I have written so far on this (borrowed from a CodeFights question). The idea is to append the counts of each element in the string and add it to the string1count and string2count variables. Then, compare the counts at each index, and if they are not equal, we can assume that it is not a valid substitution cipher since each element in the array needs to have the same number of corresponding of characters in order to be a substitution cipher.
def isSubstitutionCipher(string1, string2):
string1count = []
string2count = []
for i in range(0,len(string1)):
string1count.append(string1.count(string1[i]))
for i in range(0,len(string2)):
string2count.append(string2.count(string2[i]))
for i in range(0,len(string1count)):
if string1count.count(string1count[i])!=string2count.count(string1count[i]):
return False
return True
Does anyone else have other proposals on how to solve this very general question / problem statement?
you could try to re-create the subsitution:
def isSubstitutionCipher(string1, string2):
if len(string1) != len(string2):
return False
subst = {}
for c1, c2 in zip(string1, string2):
if c1 in subst:
if c2 != subst[c1]:
return False
else:
if c2 in subst.values():
return False
subst[c1] = c2
return True
for all the characters you have already seen, make sure the substitution matches. for the new ones: store them in the substitution and make sure they are not already a substitution target.
this will return False at the first character that does not match.
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