题解 | #识别有效的IP地址和掩码并进行分类统计#

花了两个半小时，就一直调试

import java.io.*;
public class Main{
    //public static 
    public static void main(String[] args) throws IOException{
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        //Scanner sc=new Scanner(System.in);
        int counts[]=new int[7];
        String s=null;
        while((s=br.readLine())!=null){
            //s=sc.next();
            String[] str1=s.split("~");
            
            String[] str2=str1[0].split("\\.");
            //String[] str3=str1[1].split("\\.");
            char chars[][]=new char[4][8];
            if(isYanma(str1[1])==false&&
               Integer.parseInt(str2[0])!=0&&Integer.parseInt(str2[0])!=127) {
                counts[5]=counts[5]+1;
                continue;
            }
            if(isValidIp(counts,str1[0])==false) {
                counts[5]=counts[5]+1;
                continue;
            }
            }
        for(int i=0;i<counts.length;i++){
                System.out.print(counts[i]+" ");
        }
    }
    public static boolean isValidIp(int[] counts,String s){
        String[] str=s.split("\\.");
        if(Integer.parseInt(str[0])==0||Integer.parseInt(str[0])==127) return true;
        for(int i=0;i<str.length;i++){
            if("".equals(str[i])) {
                //System.out.println(str[i]);
                return false;
            }
            int val=Integer.parseInt(str[i]);
            if(val<0&&val>255) return false;
        }
        
        int val=Integer.parseInt(str[0]);
        if(val==10){
            counts[6]++;
            counts[0]++;
        }else if(val==192&&Integer.parseInt(str[1])==168){
             counts[6]++;
            counts[2]++;
        }
        else if(val==172&&Integer.parseInt(str[1])>=16
                  &&Integer.parseInt(str[1])<=31) {
            counts[6]++;
        }
        else if(val>=1&&val<=126) counts[0]++;
        else if(val>=128&&val<=191) counts[1]++;
        else if(val>=192&&val<=223) counts[2]++;
        else if(val>=224&&val<=239) counts[3]++;
        else if(val>=240&&val<=255) counts[4]++;
        else return false;
        return true;
    }
    public static boolean isYanma(String s){
        String str[]=s.split("\\.");
        int flag=0;
        int count11=0;
        for(int i=0;i<str.length;i++){
            int count=0;
            int val=Integer.parseInt(str[i]);
            if(flag==1 && (val&128)==128) return false;
            while((val&128)==128){
                count++;
                count11++;
                val=val<<1;
                //System.out.println(count+" "+val);
                
            }
            if(((val&128)!=128)&&count<8) flag=1;
            for(int j=0;j<8-count;j++){
                if((val&128)==128&&flag==1){
                    return false;
                    
                }
                 val=val<<1;
            }
           
        }
        if(count11==32||count11==0) return false;
        return true;
    }
}