Problem URL: Check if a string contains all binary codes of size k

First we will divide the string to all possible substring of length k. Then add all of them into a hashset. If the length of the hashset is equals to 2^k, then we found all possible number and return true, else return false.

class Solution:
    def hasAllCodes(self, s: str, k: int) -> bool:
        kCodes = set()
        for i in range(len(s)-k+1):
            kCodes.add(s[i:i+k])
        return len(kCodes) == 2**k

Time Complexity: O(n*k) Space Complexity: O(n*k)