Minimum time to revert word to initial state i

String Rolling Hash String Matching Hash Function

42.3% acceptance

Feb 25, 2026

176

You are given a 0-indexed string word and an integer k. At every second, you must perform the following operations: Remove the first k characters of word. Add any k characters to the end of word. Return the minimum time greater than zero required for word to revert to its initial state.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn minimum_time_to_initial_state(word: String, k: i32) -> i32 {
    let n = word.len();
    let k = k as usize;
    let w = word.as_bytes();
    for t in 1.. {
      let skip = t * k;
      if skip >= n { return t as i32; }
      if w[skip..] == w[..n-skip] { return t as i32; }
    }
    unreachable!()
  }
}