java实现识别有效IP并分类

字符串分割，暴力判断。。。默默吐槽一下牛客的题目描述，规则不清晰，IP和掩码只要其中一个非法，另一个就不判断了，直接下一组。。给的示例正好有误导作用，试了好几遍才摸清这个规则。。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    private static int a = 0, b = 0, c = 0, d = 0, e = 0, error = 0, privateIp = 0;
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String str = "";

        while ((str = reader.readLine()) != null){
            final String[] strings = str.split("~");
            final String[] ip = strings[0].split("\\.");
            final String[] mask = strings[1].split("\\.");
            if (checkIp(ip) && checkIp(mask) && checkMask(mask)){
                checkIpKind(ip);
            }else {
                error++;
            }
        }
        System.out.println(a + " " + b + " " + c + " " + d + " " + e + " " + error + " " + privateIp);
        reader.close();
    }

    public static void checkIpKind(String[] ip){
        if (ip.length == 4){
            int first = Integer.parseInt(ip[0]);
            int second = Integer.parseInt(ip[1]);
            if (first == 0 || first == 127) return;
            // 先判断是不是私有的
            if (first == 10 || (first == 172 && second <= 31 && second >= 16)
                    || (first == 192 && second == 168)) {
                privateIp++;
            }
            // 判断其他类
            if (first >= 1 && first <= 126){
                a++;
            }else if (first >= 128 && first <= 191){
                b++;
            }else if (first >= 192 && first <= 223){
                c++;
            }else if (first >= 224 && first <= 239)
                d++;
            else if (first >= 240 && first <= 255) e++;
        }
    }

    public static boolean checkIp(String[] ip){
        if (ip.length != 4) return false;
        for (int i = 0; i < ip.length; i++) {
            if (ip[i].equals("")) return false;
            int anInt = Integer.parseInt(ip[i]);
            if (anInt > 255 || anInt < 0) return false;
        }
        Long unsinged = ip2Unsinged(ip);
        final String binaryString = Long.toBinaryString(unsinged);
        if (!binaryString.contains("1") || !binaryString.contains("0")) return false;
        return true;
    }

    public static Long ip2Unsinged(String[] ip){
        Long unsinged = 0L;
        for (int i = 0; i < ip.length; i++) {
            unsinged |= Long.parseLong(ip[i]) << 8 * (ip.length - i - 1);
        }
        return unsinged;
    }

    public static boolean checkMask(String[] mask){
        if (mask.length != 4) return false;
        Long unsinged = ip2Unsinged(mask);
        boolean cantZero = true;
        while (unsinged != 0){
            final long bit = unsinged & 0x01;
            if (bit == 0) {
                unsinged >>>= 1;
                if (!cantZero) return false;
                cantZero = true;
                continue;
            }
            unsinged >>>= 1;
            cantZero = false;
        }

        return true;
    }
}