public boolean check(String s1, String s2) {
if (s1.equals(s2)) return true;
if (s1.length() == 1) return false;
HashMap<Character, Integer> map = new HashMap<Character, Integer>();
for (int i = 0; i < s1.length(); i++) {
char c = s1.charAt(i);
if (map.containsKey(c)) map.put(c, map.get(c) + 1);
else map.put(c, 1);
}
for (int i = 0; i < s2.length(); i++) {
char c = s2.charAt(i);
if (map.containsKey(c)) map.put(c, map.get(c) - 1);
else return false;
}
for (Map.Entry<Character, Integer> entry : map.entrySet()) {
int val = entry.getValue().intValue();
if (val != 0) return false;
}
for (int i = 1; i < s1.length(); i++) {
String left_s1 = s1.substring(0, i);
String right_s1 = s1.substring(i);
String left_s2 = s2.substring(0, i);
String right_s2 = s2.substring(i);
if (check(left_s1, left_s2) && check(right_s1, right_s2)) return true;
}
for (int i = 1; i < s1.length(); i++) {
String left_s1 = s1.substring(0, i);
String right_s1 = s1.substring(i);
String left_s2 = s2.substring(0, s1.length() - i);
String right_s2 = s2.substring(s1.length() - i);
if (check(left_s1, right_s2) && check(right_s1, left_s2)) return true;
}
return false;
}
