题解 | #识别有效的IP地址和掩码并进行分类统计#

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner fzhinput = new Scanner(System.in);
        int a = 0, b = 0, c = 0, d = 0, e = 0, ff = 0, pnum = 0;
        while (fzhinput.hasNextLine()) {
            String srdz = fzhinput.nextLine();
            String dz[] = srdz.split("~");
            if (dz.length != 2) {
                ff++;
                continue;
            } 
            String ipdz[] = dz[0].split("\\.");
            String zwym[] = dz[1].split("\\.");
            int sz, sz1;
            sz = Integer.parseInt(ipdz[0]);
            if (!isValIP(ipdz) || !isValYM(zwym)) {
                if (sz == 127 || sz == 0) {

                } else {
                    ff++;
                    
                    continue;
                }
            } 
            
            if (sz >= 1 && sz <= 126) {
                a++;
            } else if (sz >= 128 && sz <= 191) {
                b++;
            } else if (sz >= 192 && sz <= 223) {
                c++;
            } else if (sz >= 224 && sz <= 239) {
                d++;
            } else if (sz >= 240 && sz <= 255) {
                e++;
            }
            sz1 = Integer.parseInt(ipdz[1]);
            if (sz == 10) {
                pnum++;
            } else if (sz == 172 && sz1 <= 31 && sz1 >= 16 ) {
                pnum++;
            } else if (sz == 192 && sz1 == 168) {
                pnum++;
            }

        }
        System.out.println(a+" "+b+" "+c+" "+d+" "+e+" "+ff+" "+pnum);


    }
    public static boolean isValIP(String[] ipdz) {
        boolean result = true;
        if (ipdz.length != 4) {
            result = false;
        } 
        else {
            for (int i = 0; i < ipdz.length; i++) {
                int num = Integer.parseInt(ipdz[i]);
                if (num > 255 || num < 0) {
                    result = false;
                }
            }
        }
        return result;
    }
    public static boolean isValYM(String[] zwym) {
        boolean result = true;
        StringBuilder stack = new StringBuilder();
        if (zwym.length != 4) {
            result = false;
        } 
        else {
            for (int i = 0; i < zwym.length; i++) {
                int num = Integer.parseInt(zwym[i]);
                String erjz = String.format("%8s",Integer.toBinaryString(num)).replace(" ","0");
                stack.append(erjz);
                if (num > 255 || num < 0) {
                    result = false;
                }
            }
            String nerjz = stack.toString();
            if(nerjz.equals("00000000000000000000000000000000")||nerjz.equals("11111111111111111111111111111111")){
                result = false;
            }
            else if(nerjz.matches("^1+0*$")){
                result = true;
            }
            else{
                result = false;
            }
        }
        return result;
    }
}