Group anagrams

Array Hash Table String Sorting

72.2% acceptance

Jan 12, 2026

21889

750

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

Solution

Rust

Time O(n²)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn group_anagrams(strs: Vec<String>) -> Vec<Vec<String>> {
    use std::collections::HashMap;
    
    let mut map: HashMap<[u8; 26], Vec<String>> = HashMap::new();
    
    for s in strs {
      // Create frequency count array as key (faster than sorting)
      let mut count = [0u8; 26];
      for byte in s.bytes() {
        count[(byte - b'a') as usize] += 1;
      }
      
      // Add the original string to the group
      map.entry(count).or_insert_with(Vec::new).push(s);
    }
    
    // Convert the HashMap values to a vector
    map.into_values().collect()
  }
}