Is Minimum Length of Anagram Concatenation easy or hard?

Minimum Length of Anagram Concatenation is rated Medium because it requires recognizing the relationship between anagram blocks and frequency ratios. The brute-force divisor approach is straightforward, but discovering the GCD optimization requires deeper insight into counting and number theory.

Minimum Length of Anagram Concatenation Python/Java solution

Most implementations use a frequency array and a GCD function. Python solutions typically rely on collections.Counter and math.gcd, while Java implementations use an int[26] array and iterative GCD computation. Both versions achieve O(n) time complexity.

How to solve Minimum Length of Anagram Concatenation in O(n)?

Count the frequency of each character in the string and compute the GCD of all counts. This GCD represents the number of anagram blocks the string can be divided into. Divide each frequency by the GCD and sum them to get the minimal base string length. The entire computation requires only a single pass over the string.

What is the best approach for Minimum Length of Anagram Concatenation?

The most efficient approach uses character frequency counting and the greatest common divisor (GCD) of all counts. If the string is composed of multiple anagram blocks, each block must maintain the same frequency ratio. Computing the GCD normalizes these counts and directly yields the smallest base string length. This solution runs in O(n) time with constant extra space.

Is Minimum Length of Anagram Concatenation asked at Google/Amazon/Meta?

Problems involving anagrams, frequency counting, and GCD patterns frequently appear in interviews at companies like Amazon, Google, and Meta. Variations often test your ability to combine hash maps with mathematical insights such as divisibility or greatest common divisor calculations.

What data structure is used in Minimum Length of Anagram Concatenation?

The primary data structure is a frequency map or fixed-size array used for character counting. This structure tracks how many times each letter appears in the string. The counts are then processed with a GCD calculation to determine the smallest repeating anagram block.

What is the time complexity of Minimum Length of Anagram Concatenation?

The optimal solution runs in O(n) time where n is the length of the string. You scan the string once to compute character frequencies and then calculate the GCD across those counts. Space complexity is O(1) because the alphabet size is fixed (typically 26 lowercase letters).

Description Hints 2 Solution Video 13:15

3138. Minimum Length of Anagram Concatenation

Medium39.8% acceptance2 companies

You are given a string s, which is known to be a concatenation of anagrams of some string t.

Return the minimum possible length of the string t.

An anagram is formed by rearranging the letters of a string. For example, "aab", "aba", and, "baa" are anagrams of "aab".

Example 1:

Input: s = "abba"

Output: 2

Explanation:

One possible string t could be "ba".

Example 2:

Input: s = "cdef"

Output: 4

Explanation:

One possible string t could be "cdef", notice that t can be equal to s.

Constraints:

1 <= s.length <= 10⁵
s consist only of lowercase English letters.

Asked at 2 companies

Turing UKG

Topics

Hints open one at a time

Hint 1

The answer should be a divisor of s.length.

Hint 2

Check each candidate naively.

13:15

Still stuck?Read 3 approaches, or watch a walkthrough.

Open solution

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1class Solution:
2    def minAnagramLength(self, s: str) -> int:
3        

Starter codePython 3Spaces: 4

Examples

Case 1Case 2Case 3

Input

"abba"

Input

"cdef"

Input

"abcbcacabbaccba"

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