1461.check-if-a-string-contains-all-binary-codes-of-size-k.md

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

Hash Table

We add all substrings of length k into a hash set. If the size of the hash set is equal to 2^k, we return true. Otherwise, we return false.

fun hasAllCodes(s: String, k: Int): Boolean {
    val substrings = HashSet<String>()
    for (i in 0..s.length - k) {
        substrings.add(s.substring(i, i + k))
    }
    return substrings.size == 2.0.pow(k).toInt()
}