leetcode

0 class Solution {

1 public:

2 bool hasAllCodes(const string &s, const int k) const {

3 static int seen[1 << 20];

4

5 if (size(s) < (1 << k) + k - 1) return false;

6

7 int crnt = 0;

8 for (int i = 0; i < k; i++) {

9 crnt = (crnt << 1) | (s[i] & 1);

10 }

11

12 const int mask = (1 << k) - 1;

13 int res = 0;

14

15 memset(seen, 0x00, sizeof(seen));

16 for (int i = k; i < size(s); i++) {

17 if (!seen[crnt]) seen[crnt] = true, res++;

18 crnt = ((crnt << 1) | (s[i] & 1)) & mask;

19 }

20 if (!seen[crnt]) seen[crnt] = true, res++;

21 return res == (1 << k);

22 }

23 };