[2017腾讯校招在线笔试题]

import java.util.ArrayList;
import java.util.Scanner;

public class Main {

    public static ArrayList rst = new ArrayList();

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            rst = new ArrayList<>();
            int input = in.nextInt();
            search(input);
            print();
        }
    }

    public static void search(int target) {
        int start = -90;
        int end = 90;

        while (rst.size() < 6) {
            int mid = (start + end) / 2;
            if (target < mid) {
                rst.add(0);
                end = mid;
            } else {
                rst.add(1);
                start = mid;
            }
        }

    }

    public static void print() {
        for (int each : rst) {
            System.out.print(each);
        }
    }
}

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int input = in.nextInt();
        int count = 0;
        for (int i = 2; i <= input / 2; i++) {
            if (isZhi(i) && isZhi(input - i)) {
                System.out.print(i);
                System.out.println(input - i);
                count++;
            }
        }
        System.out.println(count);
    }

    public static boolean isZhi(int tar) {
        if (tar < 2) {
            return false;
        }
        for (int i = 2; i * i <= tar; i++) {
            if (tar % i == 0) {
                return false;
            }
        }
        return true;
    }
}