LeetCode-in-Java
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 * 105s[i]is either'0'or'1'.1 <= k <= 20
Solution
import java.util.HashSet;
import java.util.Set;
public class Solution {
public boolean hasAllCodes(String s, int k) {
int total = (int) Math.pow(2, k);
int start = 0;
int end = start + k;
Set<String> st = new HashSet<>();
while (end <= s.length()) {
String sbStr = s.substring(start, end);
st.add(sbStr);
if (st.size() == total) {
return true;
}
start++;
end++;
}
return false;
}
}