How should I practice Longest Perfect Anagrams?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Amazon online assessment problems in FastPrep.

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Problem · String

Longest Perfect Anagrams

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Problem statement

Developers at Amazon continuously develop algorithms to ensure the security of users' accounts through strong passwords.

One such algorithm is based upon the concept of perfect anagrams.

A string x is an anagram of y if it is possible to rearrange the letters in x to get y. For example, "bat" and "tab" are anagrams, 'bats' and 'tab' are not.
Two strings a and b are said to be perfect anagrams if a and b are anagrams of each other and a is not equal to b.

For example,

Strings "dog" and "god" are anagrams and perfect anagrams.

Strings "baba" and "baba" are anagrams but not perfect anagrams because the strings are equal.

Strings "abbac" and "caaba" are not anagrams because they do not contain exactly the same characters.

Given a string s, find the maximum length of two of its substrings that are perfect anagrams. If no such substrings exist, return -1.

Note: A substring is a contiguous subsegment of a string. For example, "xy" is a substring of "xyz" but "xz" is not.

Function

longestPerfectAnagrams(s: String) → int

Complete the function longestPerfectAnagrams in the editor.

longestPerfectAnagrams has the following parameter:

string s: a string

Returns

int: the length of the longest substring pair which are perfect anagrams or -1 if no such pair exists.

Examples

Example 1

s = "abcacb"return = 4

The string s = "abcacbab",

Pairs of substrings such as ("ca", "ac"), ("abc", "acb"), ("bca", "acb"), ("bcac", "cacb"), etc. are perfect anagrams.
Among these, the longest are ("bcac", "cacb").

It can be proven that no two substrings of length greater than 4 in the given string are perfect anagrams. Return 4.

Example 2

s = "cabcab"return = 3

("cab","bca") , ('abc,'bca'') are two such 3 length substrings

Example 3

s = "aabbcc"return = -1

There are no perfect anagram. a & a , b&b , c& c are exctly same.

Constraints

1 ≤ |s| ≤ 10^5
string s contains lowercase English characters only.