Check If a String Contains All Binary Codes of Size K

Description

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 indicies 0, 1, 3 and 2 respectively.

Example 2:

Input: s = "00110", k = 2
Output: true

Example 3:

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 4:

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

Example 5:

Input: s = "0000000001011100", k = 4
Output: false

 

Constraints:

• 1 <= s.length <= 5 * 10^5
• s consists of 0's and 1's only.
• 1 <= k <= 20

Solution(javascript)

/** Sliding Window
 * @param {string} s
 * @param {number} k
 * @return {boolean}
 */
const hasAllCodes = function (s, k) {
  const set = new Set()
  for (let i = 0; i <= s.length - k; i++) {
    const str = s.substr(i, k)
    set.add(str)
  }
  return set.size === (2 ** k)
}