Find and replace pattern

Array Hash Table String

77.0% acceptance

Feb 22, 2026

4025

174

Given a list of strings words and a string pattern, return a list of words[i] that match pattern. You may return the answer in any order. A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word. Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter.

Solution

Rust

Time O(2^n)

Space O(n)

LeetCode

solution.rs

/*
 * Given a list of strings words and a string pattern, return a list of words[i] that match pattern. You may return the answer in any order.
 * A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word.
 * Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter.
 * Example 1:
 * Input: words = ["abc","deq","mee","aqq","dkd","ccc"], pattern = "abb"
 * Output: ["mee","aqq"]
 * Explanation: "mee" matches the pattern because there is a permutation {a -> m, b -> e, ...}.
 * "ccc" does not match the pattern because {a -> c, b -> c, ...} is not a permutation, since a and b map to the same letter.
 * Example 2:
 * Input: words = ["a","b","c"], pattern = "a"
 * Output: ["a","b","c"]
 * Constraints:
 * 1 <= pattern.length <= 20
 * 1 <= words.length <= 50
 * words[i].length == pattern.length
 * pattern and words[i] are lowercase English letters.
 */

impl Solution {
  fn normalize(s: &str) -> Vec<usize> {
    let mut map = std::collections::HashMap::new();
    let mut cnt = 0usize;
    s.chars().map(|c| {
      let n = map.entry(c).or_insert_with(|| { let v = cnt; cnt += 1; v });
      *n
    }).collect()
  }
  pub fn find_and_replace_pattern(words: Vec<String>, pattern: String) -> Vec<String> {
    let pat = Self::normalize(&pattern);
    words.into_iter().filter(|w| Self::normalize(w) == pat).collect()
  }
}