给定两个字符串，检查它们是否k相等，长度为k的每个子串都出现在这两个字符串上，并且必须是max

function isKEqual(str1, str2, k) {
  if (str1.length !== str2.length) {
    return false;
  }

  for (let i = 0; i <= str1.length - k; i++) {
    const subStr = str1.substring(i, i + k);
    if (!str2.includes(subStr)) {
      return false;
    }
  }

  return true;
}

const str1 = "abcd";
const str2 = "bcda";
const k = 2;
console.log(isKEqual(str1, str2, k)); // Output: true

public class KMP {
    public static boolean isKEqual(String str1, String str2, int k) {
        if (str1.length() != str2.length()) {
            return false;
        }

        for (int i = 0; i <= str1.length() - k; i++) {
            String subStr = str1.substring(i, i + k);
            if (!str2.contains(subStr)) {
                return false;
            }
        }

        return true;
    }

    public static void main(String[] args) {
        String str1 = "abcd";
        String str2 = "bcda";
        int k = 2;
        System.out.println(isKEqual(str1, str2, k)); // Output: true
    }
}