public boolean wordPatternMatch(String pattern, String str) {

if (pattern.length() == 0) return str.length() == 0;

if (str.length() == 0) return false;

return match(pattern, 0, str, 0, new String[26], new HashMap<>());

}

private boolean match(String pattern, int i, String str, int j, String[] p2s, Map<String, Character> s2p) {

if (i == pattern.length()) return j == str.length();

if (j == str.length()) return false;

char p = pattern.charAt(i);

if (p2s[p-'a'] != null) {

String sub = p2s[p-'a'];

if (!str.startsWith(sub, j)) return false;

if (match(pattern, i+1, str, j+sub.length(), p2s, s2p)) return true;

} else {

for (int k=j+1; k<=str.length(); k++) {

String sub = str.substring(j, k);

if (s2p.containsKey(sub)) {

char p0 = s2p.get(sub);

if (p0 != p) continue;

if (match(pattern, i+1, str, j+sub.length(), p2s, s2p)) return true;

} else {

p2s[p-'a'] = sub;

s2p.put(sub, p);

if (match(pattern, i+1, str, j+sub.length(), p2s, s2p)) return true;

p2s[p-'a'] = null;

s2p.remove(sub);

}

}

}

return false;

}