Longest Common Prefix using Binary Search

StringUtil.java

//package ;

/**
 * @see  <a href="https://www.geeksforgeeks.org/longest-common-prefix-using-binary-search/">Longest
 *              Common Prefix using Binary Search</a>
 */
public class StringUtil {

    public static String commonPrefix(CharSequence... strings) {
        int low = 0, high = minLength(strings) - 1;
        while (low <= high) {
            int mid = low + (high - low) / 2;
            if (startWith(strings, low, mid)) {
                low = mid + 1;
            } else {
                high = mid - 1;
            }
        }
        return (low == 0) ? "" : strings[0].subSequence(0, low).toString();
    }

    private static boolean startWith(CharSequence[] strings, int start, int end) {
        CharSequence prefix = strings[0];
        for (int i = 1, n = strings.length; i < n; i++) {
            CharSequence str = strings[i];
            for (int j = start; j <= end; j++) {
                if (str.charAt(j) != prefix.charAt(j)) {
                    return false;
                }
            }
        }
        return true; 
    }

    private static int minLength(CharSequence[] strings) {
        int min = Integer.MAX_VALUE;
        for (int i = 0, n = strings.length; i < n; i++) {
            int len = strings[i].length();
            if (len < min) {
                min = len;
            }
        }
        return min;
    }

    public static void main(String[] args) {
        System.out.println(commonPrefix("geeksforgeeks", "geeks", "geek", "geezer"));
        System.out.println(commonPrefix("apple", "ape", "april"));
        System.out.println(commonPrefix("abcd"));
    }

}