Word Pattern II

这道题得和I联动

    boolean res = false;
    Map<String, Character> map = new HashMap<>();
    Set<Character> set = new HashSet<>();
    public boolean wordPatternMatch(String pattern, String str) {
        helper(pattern, 0, str, 0);
        return res;
    }
    
    private void helper(String pattern, int p, String str, int s){
        if (p == pattern.length() && s == str.length()) {
            res = true;
            return;
        }
        if (p >= pattern.length() || s >= str.length()) {
            return;
        }
        char c = pattern.charAt(p);
        for (int i = s + 1; i <= str.length(); i++) {
            String substr = str.substring(s, i);
            if (!map.containsKey(substr) && !set.contains(c)) {
                map.put(substr, c);
                set.add(c);
                helper(pattern, p + 1, str, i);
                set.remove(c);
                map.remove(substr);
            } else if (map.containsKey(substr) && map.get(substr) == c) {
                helper(pattern, p + 1, str, i);
            }
        }
    }