题解 | #手机号#

import java.util.HashSet;
import java.util.Scanner;

public class Main {
    // 中国电信: 133,153,180,181,189
    private static final HashSet<String> telecomSet = new HashSet<String>(){{
        add("133");
        add("153");
        add("180");
        add("181");
        add("189");
    }};
    // 中国联通: 130,131,155,185,186
    private static final HashSet<String> unicomSet = new HashSet<String>(){{
        add("130");
        add("131");
        add("155");
        add("185");
        add("186");
    }};
    // 中国移动: 135,136,150,182,188
    private static final HashSet<String> mobilecomSet = new HashSet<String>(){{
        add("135");
        add("136");
        add("150");
        add("182");
        add("188");
    }};

    private static final int LEN = 11;

    public static void main(String[] args){
        Scanner in = new Scanner(System.in);

        while(in.hasNext()){
            solution1(in);
            // solution2(in);
        }
    }

    /**
     * 字符串: 正则
     * @param in
     */
    private static void solution1(Scanner in){
        int N = Integer.parseInt(in.nextLine());

        String number,prefix;
        for(int i=1; i<=N; i++){
            number = in.nextLine();
            if(number.matches("(133|153|180|181|189)\\d{8}")){
                System.out.println("China Telecom");
            }else if(number.matches("(130|131|155|185|186)\\d{8}")){
                System.out.println("China Unicom");
            }else if(number.matches("(135|136|150|182|188)\\d{8}")){
                System.out.println("China Mobile Communications");
            }else{
                System.out.println(-1);
            }
        }
    }
    
    /**
     * 字符串: Set
     * @param in
     */
    private static void solution2(Scanner in){
        int N = Integer.parseInt(in.nextLine());

        String number,prefix;
        for(int i=1; i<=N; i++){
            number = in.nextLine();
            if(number.length() != LEN){
                System.out.println(-1);
            }else{
                prefix = number.substring(0, 3);
                if(telecomSet.contains(prefix)){
                    System.out.println("China Telecom");
                }else if(unicomSet.contains(prefix)){
                    System.out.println("China Unicom");
                }else if(mobilecomSet.contains(prefix)){
                    System.out.println("China Mobile Communications");
                }else{
                    System.out.println(-1);
                }
            }
        }
    }
}