Find and Replace Pattern

题目
You have a list of words and a pattern, and you want to know which words in words matches the pattern.

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.)

Return a list of the words in words that match the given pattern.

You may return the answer in any order.

答案
跟word pattern II的思路完全一样，而且更简单不需要backtracking

class Solution {
    public List<String> findAndReplacePattern(String[] words, String pattern) {
        List<String> list = new ArrayList<>();

        for(int i = 0; i < words.length; i++) {
            Map<Character, Character> map = new HashMap<>();
            Set<Character> taken = new HashSet<>();

            boolean matched = true;
            if(words[i].length() == pattern.length()) {
                for(int j = 0; j < words[i].length(); j++) {
                    char pc = pattern.charAt(j);
                    char wc = words[i].charAt(j);
                    Character mapping = map.get(pc);
                    if(mapping == null) {
                        if(taken.contains(wc)) {
                            matched = false;
                            break;
                        }
                        taken.add(wc);
                        map.put(pc, wc);
                    }
                    else {
                        if(wc != mapping) {
                            matched = false;
                            break;
                        }
                    }
                }
                if(matched) list.add(words[i]);
            }
        }
        return list;
    }
}