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.

class Solution:
    def findAndReplacePattern(self, words: List[str], pattern: str) -> List[str]:
    /*only need to care about the first index of each character*/
        def normalize(word):
            mapping = {}
            return [mapping.setdefault(c, len(mapping)) for c in word]

        normalized_pattern = normalize(pattern)
        return [w for w in words if normalize(w) == normalized_pattern]