Find the Lexicographically Largest String From the Box II Python/Java solution

Most implementations follow the same structure: maintain indices i, j, and offset k to compare candidate substrings. When characters differ, advance the pointer representing the smaller substring and reset the offset. This logic translates directly to Python, Java, C++, Go, or TypeScript.

What is the best approach for Find the Lexicographically Largest String From the Box II?

The optimal approach uses a two pointers maximum suffix algorithm. Two candidate starting indices are compared character by character, and the weaker candidate is skipped entirely. This eliminates large ranges of substrings and finds the lexicographically largest result in O(n) time with O(1) extra space.

Is Find the Lexicographically Largest String From the Box II asked at Google/Amazon/Meta?

Hard string comparison and lexicographic optimization problems appear frequently in interviews at companies like Google, Amazon, and Meta. Variants involving suffix comparisons, greedy pointer movement, or string ranking are common in senior-level coding rounds.

What data structure is used in Find the Lexicographically Largest String From the Box II?

The solution primarily relies on string indexing and the two pointers technique. No additional data structures are required because comparisons are done directly on the input string while scanning candidate positions.

What is the time complexity of Find the Lexicographically Largest String From the Box II?

The optimal algorithm runs in O(n) time and O(1) space by scanning the string once with two moving pointers and an offset pointer for comparisons. A naive brute force approach that checks every substring requires O(n^2) time.

Description Hints 1 Solution Video 7:42

3406. Find the Lexicographically Largest String From the Box II

Q: Is Find the Lexicographically Largest String From the Box II easy or hard?

Find the Lexicographically Largest String From the Box II is classified as a Hard problem because it requires recognizing the maximum suffix pattern and implementing pointer skipping correctly. The brute force idea is simple, but achieving linear time requires deeper string algorithm insight.

Q: How to solve Find the Lexicographically Largest String From the Box II in O(n)?

Use a maximum suffix style two-pointer scan. Maintain two candidate starting indices and compare characters using an offset. When a mismatch occurs, discard the lexicographically smaller candidate and jump its pointer past the compared region. This guarantees each character is processed only a constant number of times.

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You are given a string word, and an integer numFriends.

Alice is organizing a game for her numFriends friends. There are multiple rounds in the game, where in each round:

word is split into numFriends non-empty strings, such that no previous round has had the exact same split.
All the split words are put into a box.

Find the lexicographically largest string from the box after all the rounds are finished.

A string a is lexicographically smaller than a string b if in the first position where a and b differ, string a has a letter that appears earlier in the alphabet than the corresponding letter in b.
If the first min(a.length, b.length) characters do not differ, then the shorter string is the lexicographically smaller one.

Example 1:

Input: word = "dbca", numFriends = 2

Output: "dbc"

Explanation:

All possible splits are:

"d" and "bca".
"db" and "ca".
"dbc" and "a".

Example 2:

Input: word = "gggg", numFriends = 4

Output: "g"

Explanation:

The only possible split is: "g", "g", "g", and "g".

Constraints:

1 <= word.length <= 2 * 10⁵
word consists only of lowercase English letters.
1 <= numFriends <= word.length

Topics

String Two Pointers

Hints open one at a time

Hint 1

Use suffix array.

7:42

Still stuck?Read the written solution, or watch a walkthrough.

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1class Solution:
  def solve(self):
      pass


Starter codePython 3Spaces: 4

Examples

Case 1Case 2

Input

"dbca"
2

Input

"gggg"
4

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