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 sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String ip = sc.nextLine();
            long num = sc.nextLong();
            intonum(ip);
            intoip(num);

        }
    }

    private static void intonum(String ip) {
//        Integer.parseInt(ip);
//        System.out.println(Integer.toString(Integer.parseInt(ip),2));
        String[] str = new String[4];
        str = ip.split("\\.");
        StringBuilder sb = new StringBuilder();
//        1010011 11000001
        for (String s : str
            ) {

            String s1 = Integer.toString(Integer.parseInt(s), 2);
            while (s1.length() % 8 != 0) {
                s1 = "0" + s1;
            }
            sb.append(s1);
        }
        System.out.println(Long.parseLong(sb.toString(), 2));
//        10110111 00011111 01001011 00010110
    }

    private static void intoip(long num) {
        String str = Long.toBinaryString(num);
        while (str.length() % 8 != 0) {
            str = "0" + str;
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < str.length() - 7; i = i + 8) {
            String tmp = str.substring(i, i + 8);
            int i1 = Integer.parseInt(tmp, 2);
            sb.append(i1);
            if (i != str.length() - 8) {
                sb.append(".");
            }
        }
//            String.format()
//            System.out.println(str);
        System.out.println(sb);
//            1010000000000000001111000001
//            00001010000000000000001111000001
//            00001010000000000000001111000001
//            00001010000000000000001111000001
//            String s=sc.nextLine();
//            System.out.println(Integer.parseInt(s,2));
    }
}