1 class Solution {
2 public:
3 typedef unordered_map<string,int> HashMap;
4 bool canMatch(const char* head, const char * end, HashMap & flags, int l){
5 if (head == end+1)
6 return true;
7 string s="";
8 for (int i=0; i<l; i++)
9 s+= *(head+i);
10 HashMap::iterator hi = flags.find(s);
11 if (hi==flags.end() || hi->second<=0)
12 return false;
13 flags[s]--;
14 bool rlt = canMatch(head+l,end,flags,l);
15 flags[s]++;
16 return rlt;
17 }
18 vector<int> findSubstring(string S, vector<string> &L) {
19 // IMPORTANT: Please reset any member data you declared, as
20 // the same Solution instance will be reused for each test case.
21 vector<int> rlt;
22 int n = L.size();
23 if (n<=0)
24 return rlt;
25 int l = L[0].length();
26 if (l<=0)
27 return rlt;
28 HashMap flags;
29 for (int i=0; i<n; i++){
30 if (flags.find(L[i]) == flags.end())
31 flags[L[i]]=1;
32 else flags[L[i]]++;
33 }
34 const char * head = S.c_str();
35 for (int i=0; i+l*n<=S.length(); i++){
36 if (canMatch(head+i, head+i+l*n-1, flags, l))
37 rlt.push_back(i);
38 }
39 return rlt;
40 }
41 };
