1   public List<Integer> findSubstring(String s, String[] words) {

 2         if (s == null || words == null || words.length == 0 || s.length() == 0) return new ArrayList<>();

 3

 4         int i, j, k, z;

 5         HashMap<String, Integer> MAP = new HashMap<>();

 6         HashMap<String, Integer> map = new HashMap<>();

 7         ArrayList<Integer> al = new ArrayList<>();

 8         StringBuilder sb = new StringBuilder(s);

 9

10         for (i = 0; i < words.length; i++) MAP.put(words[i], MAP.getOrDefault(words[i], 0) + 1);

11

12         int len = words[0].length();

13

14         String tmp, t2;

15         for (k = 0; k < len; k++) {

16             map.clear();

17             map.putAll(MAP);

18

19             OUT:

20             for (i = k, j = k; j + len <= s.length(); j += len) {

21                 tmp = sb.substring(j, j + len);

22                 if (!map.containsKey(tmp)) {

23                     for (z = i; z < j; z += len) {

24                         tmp = sb.substring(i, i + len);

25                         map.put(tmp, map.get(tmp) + 1);

26                     }

27                     i = j + len;

28                     continue;

29                 }

30                 map.put(tmp, map.get(tmp) - 1);

31                 while (map.get(tmp) < 0 && i + len <= j) {

32                     t2 = sb.substring(i, i + len);

33

34                     map.put(t2, map.get(t2) + 1);

35                     i += len;

36                 }

37                 for (Integer v : map.values()) if (v != 0) continue OUT;

38                 al.add(i);

39                 t2 = sb.substring(i, i + len);

40                 map.put(t2, map.get(t2) + 1);

41                 i += len;

42             }

43         }

44         return al;

45     }