题解 | #整数与IP地址间的转换#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        // while (in.hasNextInt()) { // 注意 while 处理多个 case
        //     int a = in.nextInt();
        //     int b = in.nextInt();
        //     System.out.println(a + b);
        // }
        String ip = in.next();
        long num = in.nextLong();
        System.out.println(toNum(ip));
        System.out.print(toIp(num));

    }

    private static long toNum(String ip) {
        String[] arr = ip.split("\\.");
        String biary = "";
        for (int i = 0; i < arr.length; i++) {
            long n = Long.parseLong(arr[i]);
            String str = Long.toBinaryString(n);
            int blen = str.length();
            for (int j = 0; j < 8 - blen; j++) {
                str = "0" + str;
            }
            biary += str;
        }
        return Long.parseLong(biary, 2);
    }

    private static String toIp(long n) {
        String biary = Long.toBinaryString(n);
        int len = biary.length();
        for (int i = 0; i < 32 - len; i++) {
            biary = "0" + biary;
        }
        String ip = "";
        for (int i = 0; i < 32; i += 8) {
            
            String str = biary.substring(i, i + 8);
            int a = Integer.parseInt(str, 2);
            
            ip += a;
            if (i != 24) {
                ip += ".";
            }
        }
        return ip;
    }
}