Find words that can be formed by characters

Array Hash Table String Counting

71.5% acceptance

Feb 25, 2026

2250

189

You are given an array of strings words and a string chars. A string is good if it can be formed by characters from chars (each character can only be used once for each word in words). Return the sum of lengths of all good strings in words.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn count_characters(words: Vec<String>, chars: String) -> i32 {
    let mut chars_count = [0u32; 26];
    for c in chars.bytes() { chars_count[(c - b'a') as usize] += 1; }
    let mut result = 0;
    'outer: for word in &words {
      let mut wc = [0u32; 26];
      for c in word.bytes() { wc[(c - b'a') as usize] += 1; }
      for i in 0..26 {
        if wc[i] > chars_count[i] { continue 'outer; }
      }
      result += word.len() as i32;
    }
    result
  }
}