1461. Check If a String Contains All Binary Codes of Size K

Medium

Given a binary string s and an integer k, return true if every binary code of length k is a substring of s. Otherwise, return false.

Example 1:

Input: s = "00110110", k = 2
Output: true
Explanation: The binary codes of length 2 are "00", "01", "10" and "11". They can be all found as substrings at indices 0, 1, 3 and 2 respectively.

Example 2:

Input: s = "0110", k = 1
Output: true
Explanation: The binary codes of length 1 are "0" and "1", it is clear that both exist as a substring. 

Example 3:

Input: s = "0110", k = 2
Output: false
Explanation: The binary code "00" is of length 2 and does not exist in the array.

Constraints:

• 1 <= s.length <= 5 * 105

• s[i] is either '0' or '1'.

• 1 <= k <= 20

class Solution:
    def hasAllCodes(self, s: str, k: int) -> bool:
        # Total Possible Binary from k
        count = 1 << k
        # We will interate through given binary string s and will note down different binary substrings of length
        # k once we finish iterating if the set() contains equal possible substrings i.e 2^k then True otherwise
        # False
        group = set()
        for index in range(len(s)-k, -1, -1):
            group.add(s[index:index+k])
        return len(group) == count