Find the lexicographically largest string from the box i

Two Pointers String Enumeration

41.0% acceptance

Feb 25, 2026

487

127

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.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn answer_string(word: String, num_friends: i32) -> String {
    let n = word.len();
    let nf = num_friends as usize;
    if nf == 1 {
      return word;
    }
    let base_len = n + 1 - nf;
    let mut best = String::new();
    for i in 0..n {
      let len = base_len.min(n - i);
      let candidate = &word[i..i + len];
      if candidate > best.as_str() {
        best = candidate.to_string();
      }
    }
    best
  }
}