SubStringfromArray

public static List<Integer> findSubstring(String s, String[] words) {
List<Integer> ans = new ArrayList<>();
if (s.length() == 0 || words.length == 0 || (words.length * words[0].length() > s.length())) {
return ans;
}
Map<String, Integer> wordFreq = new HashMap<>();
for (String w : words) {
wordFreq.put(w, wordFreq.getOrDefault(w, 0) + 1);
}
int n = words.length;
int l = words[0].length();
Map<String, Integer> tmp = new HashMap<>();
for (int i = 0; i <= s.length() - (n * l); i++) {
for (int j = i; j < i + (n * l); j += l) {
tmp.put(s.substring(j, j + l), tmp.getOrDefault(s.substring(j, j + l), 0) + 1);
}
int flag = 1;
for (int j = 0; j < n; j++) {
if (!tmp.containsKey(words[j]) || !wordFreq.get(words[j]).equals(tmp.get(words[j]))) {
flag = 0;
break;
}
}
if (flag == 1) {
ans.add(i);
}
tmp.clear();
}
return ans;
}


Testcase 181 failed