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
        String a = in.next();
        long result = 0;
        String temp = "";
        int count = 0;
        for(int i = a.length()-1; i >= 0; i--){
            if(a.charAt(i)!='.'){
                temp = a.charAt(i) + temp;
            }else{
                result += Long.parseLong(temp)*Math.pow(256, count);
                count++;
                temp="";
            }
        }
        result += Long.parseLong(temp)*Math.pow(256, count);
        System.out.println(result);
        long b = in.nextLong();
        String ret = "";
        while(b!=0){
            long cur_w = (long)Math.pow(256, count);
            ret = ret + "." + String.valueOf(b/cur_w);
            b = b % cur_w; 
            count--;      
        }
        System.out.println(ret.substring(1));
    }
}