Leetcode•Oct 30, 2026
Find and Replace Pattern
Hazrat Ali
Leetcode
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"]
Solution
var findAndReplacePattern = function(words, pattern) {
function isMatch(word, pattern) {
const map1 = new Map();
const map2 = new Map();
for (let i = 0; i < word.length; i++) {
const w = word[i];
const p = pattern[i];
if (map1.has(p) && map1.get(p) !== w) {
return false;
}
if (map2.has(w) && map2.get(w) !== p) {
return false;
}
map1.set(p, w);
map2.set(w, p);
}
return true;
}
return words.filter(word => isMatch(word, pattern));
};