Find the k beauty of a number

Math String Sliding Window

63.1% acceptance

Feb 25, 2026

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The k-beauty of an integer num is defined as the number of substrings of num when it is read as a string that meet the following conditions: It has a length of k. It is a divisor of num. Given integers num and k, return the k-beauty of num. Note: Leading zeros are allowed. 0 is not a divisor of any value. A substring is a contiguous sequence of characters in a string.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn divisor_substrings(num: i32, k: i32) -> i32 {
    let s = num.to_string();
    let k = k as usize;
    let mut count = 0;
    for i in 0..=s.len()-k {
      let sub: i32 = s[i..i+k].parse().unwrap();
      if sub != 0 && num % sub == 0 {
        count += 1;
      }
    }
    count
  }
}