What's your preferred solution?
is_a_palindrome(S) {
assert is_a_string(S)
if reverse(S) == S
return true
return false
}
Unless of course the recruiter is trying to catch you pants-down, but then the parent article wouldn't post that overengineered "solution" as a gold-standard, like they did.
That's poppycock. Here are the requirments:
>> Write the most efficient function you can that determines whether a given string is a palindrome.
A palindrome is a string that is equal to itself reversed. That's like, the mathematical definition of a palindrome (simplified, of course). What I gave you catches exactly that. If some of the test cases in the proposed solution don't agree with the commonly accepted definition that's a problem of the proposed solution, not mine.
Also, in terms of the "most efficient" solution, the guy's proposed solution is far from that- because he tries to be smart and reverse the string while he compares it, thinking that's faster than going the whole hog. But that's only going to save you some cycles a tiny amount of the time, because the vast majority of strings you can expect to encounter are unlikely to be palindromes. Reversing and comparing the string to itself is the neatest, quickest, most legible and prettiest thing you can do in this case, regardless of your use case or anything else.
And if you're a recruiter that expects anything else, that's because you have no idea what you're looking for, not because you are as smart as you think you are.
>> A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward or forward. Allowances may be made for adjustments to capital letters, punctuation, and word dividers. Examples in English include “A man, a plan, a canal, Panama!”, “Amor, Roma”, “race car”, “stack cats”, “step on no pets”, “taco cat”, “put it up”, “Was it a car or a cat I saw?” and “No ‘x’ in Nixon”.
Given the last sentence, doesn't that change the meaning of your sentence to directly refute your interpretation?