Java题解

别的不难，输入输出还调试了好一会。
难点主要在于错误ip的判断上面，定义了个flag，先判断ip在判断掩码，ip只是判断了下是否为空，掩码的判断的话使用了多重判断，一位一位判断，先1后0就那8中情况，判断是不是在list范围里面就行，在去除掉两个边缘情况 全是1或者全是0。
地址范围和私有ip则直接用了个函数去做，只用传ip的前两位过去判断就行。

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

/**
 * decription:识别有效的IP地址和掩码并进行分类统计
 */
public class classify {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int[] count = {0, 0, 0, 0, 0, 0, 0};  //个数数组

        while (scanner.hasNext()) {
            String str = scanner.nextLine();

            String[] strings = str.split("~");
            String ipStr = strings[0];  //ip
//            System.out.println(ipStr);
            String codeStr = strings[1];  //掩码
//            System.out.println(codeStr);

            String[] ipCharStr = ipStr.split("\\.");
            //判断ip是否为空或者首字符是否等于0
            Boolean isTrue = true;
            int number = Integer.parseInt(ipCharStr[0]);
            if (number == 0)
               continue;              //为0直接跳出本次循环
            else {
                for (int i = 0; i < ipCharStr.length; i++) {
                    if (ipCharStr[i].length() <= 0 || ipCharStr[i] == "") {
                        isTrue = false;
                    }
                }
            }

            //如果ip地址正确判断掩码是否正确
            if (isTrue) {
                //判断掩码是否正确
                int[] codeRange = {254, 252, 248, 240, 224, 192, 128, 0};
                List<Integer> list = Arrays.stream(codeRange).boxed().collect(Collectors.toList());//int数组转化为list
                String[] codeCharStr = codeStr.split("\\.");

                //判断是否前面全为1后面全为0
                if ("255".equals(codeCharStr[0])) {
                    if ("255".equals(codeCharStr[1])) {
                        if ("255".equals(codeCharStr[2])) {
                            if ("255".equals(codeCharStr[3])) {
                                isTrue = false;
                            } else if (list.contains(Integer.parseInt(codeCharStr[3]))) {
                                isTrue = true;
                            } else
                                isTrue = false;
                        } else if (list.contains(Integer.parseInt(codeCharStr[2]))) {
                            if (Integer.parseInt(codeCharStr[3]) == 0)
                                isTrue = true;
                            else
                                isTrue = false;
                        } else
                            isTrue = false;
                    } else if (list.contains(Integer.parseInt(codeCharStr[1]))) {
                        if (Integer.parseInt(codeCharStr[2]) == 0 && Integer.parseInt(codeCharStr[3]) == 0)
                            isTrue = true;
                        else
                            isTrue = false;
                    } else
                        isTrue = false;
                } else if (list.contains(Integer.parseInt(codeCharStr[0]))) {
                    if (Integer.parseInt(codeCharStr[0]) == 0) {
                        isTrue = false;
                    } else {
                        if (Integer.parseInt(codeCharStr[1]) == 0 && Integer.parseInt(codeCharStr[2]) == 0 && Integer.parseInt(codeCharStr[3]) == 0)
                            isTrue = true;
                        else
                            isTrue = false;
                    }

                } else
                    isTrue = false;
            }

            //调用方法判断地址范围和私网ip
            if (isTrue) {
                int first = Integer.parseInt(ipCharStr[0]);
                int second = Integer.parseInt(ipCharStr[1]);
                count = judgeIp(first, second, count);
            } else {
                count[5]++;
            }
        }

        System.out.println(count[0] + " " + count[1] + " " + count[2] + " " + count[3] + " " + count[4] + " " + count[5] + " " + count[6]);
    }


    //判断地址范围和私网ip
    public static int[] judgeIp(int first, int second, int[] count) {
        //判断地址范围
        if (first >= 1 && first <= 126)
            count[0]++;
        else if (first >= 128 && first <= 191)
            count[1]++;
        else if (first >= 192 && first <= 223)
            count[2]++;
        else if (first >= 224 && first <= 239)
            count[3]++;
        else if (first >= 240 && first <= 255)
            count[4]++;

        //判断私网ip
        if (first == 192 && second == 168)
            count[6]++;
        if (first == 10)
            count[6]++;
        if (first == 172) {
            if (second >= 16 && second <= 31)
                count[6]++;
        }
        return count;
    }
}