Find all anagrams in a string

Hash Table String Sliding Window

53.3% acceptance

Jan 13, 2026

13157

375

Given two strings s and p, return an array of all the start indices of p's anagrams in s. You may return the answer in any order.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn find_anagrams(s: String, p: String) -> Vec<i32> {
    let mut result = Vec::new();
    let s_bytes = s.as_bytes();
    let p_bytes = p.as_bytes();
    
    if s.len() < p.len() {
      return result;
    }
    
    let mut p_count = vec![0; 26];
    let mut window_count = vec![0; 26];
    
    for &b in p_bytes {
      p_count[(b - b'a') as usize] += 1;
    }
    
    for i in 0..s_bytes.len() {
      window_count[(s_bytes[i] - b'a') as usize] += 1;
      
      if i >= p.len() {
        let remove_idx = i - p.len();
        window_count[(s_bytes[remove_idx] - b'a') as usize] -= 1;
      }
      
      if i + 1 >= p.len() && window_count == p_count {
        result.push((i + 1 - p.len()) as i32);
      }
    }
    
    result
  }
}