String Permuations
Given two strings, write a method to decide if one is a permutation of the other.
Solution
Complexity:
Assuming that the length are the same, we can count all the characters in one string, and see if the numbers match in the other string. For fast access we can use a hash table or an array to store the counts.
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def is_permutation(str1, str2):
hash = dict()
for char in str1:
hash[char] = hash.get(char, 0) + 1
for char in str2:
if hash.get(char, 0) == 0:
return False
hash[char] -= 1
return True
