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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

Related Topics

[Hash Table] [String] [Bit Manipulation] [Rolling Hash] [Hash Function]

Hints

Hint 1

We need only to check all sub-strings of length k.

Hint 2

The number of distinct sub-strings should be exactly 2^k.