第八届省赛 c++ B组 填空题

   第一题很简单，不再赘述

import java.util.*;

public class Main {

    //判断是否是质数
    static boolean is_prime(int x)
    {
        if (x < 2) return false;
        for (int i = 2; i <= x / i; i ++ )
            if (x % i == 0)
                return false;
        return true;
    }

    public static void main(String[] args) {
        for (int i = 2; i <= 10000; i++) {
            if(is_prime(i)){
                for(int d = 1; d <= 10000; d++){
                    int k = i;
                    int count = 0;
                    while(is_prime(k)){
                        k+=d;
                        count++;
                    }
                    if(count == 10){
                        System.out.println(d);
                        return;
                    }
                }
            }
        }
    }
}

第八届省赛 c++ C组 填空题

  第一题可以直接数出答案

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        int count = 0;
        File a = new File("data/C.txt");
        File a2 = new File("data/A.txt");
        File a3 = new File("data/B.txt");
        List list = new ArrayList<String>();
        List list2 = new ArrayList<String>();
        try {
            InputStreamReader b = new InputStreamReader(new FileInputStream(a));
            BufferedReader br = new BufferedReader(b);
            String str = br.readLine();
            while (str != null) {
                String[] q = str.split(", ");
                for (String h : q) {
                    list.add(h);
                }
                str = br.readLine();
            }
            //------------------------------------
            InputStreamReader b2 = new InputStreamReader(new FileInputStream(a2));
            BufferedReader br2 = new BufferedReader(b2);
            String str2 = br2.readLine();
            while (str2 != null) {
                String[] q = str2.split(", ");
                for (String h : q) {
                    list2.add(h);
                }
                str2 = br2.readLine();
            }
            //---------------------------------------
            InputStreamReader b3 = new InputStreamReader(new FileInputStream(a3));
            BufferedReader br3 = new BufferedReader(b3);
            String str3 = br3.readLine();
            while (str3 != null) {
                String[] q = str3.split(", ");
                for (String h : q) {
                    if (list2.contains(h) && !list.contains(h))
                        count++;
                    list2.add(h);
                }
                str3 = br3.readLine();
            }
            System.out.println(count);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

第八届省赛 java B组 填空题

  与第八届省赛 c++ B组 填空题的第一题相同

  public class Main {
    static int[] a = new int[9];
    static boolean[] st = new boolean[10];
    static int res = 0;

    static void dfs(int u) {
        if (u == 9) {
            int k1 = a[0] + a[1] + a[2] + a[3];
            int k2 = a[0] + a[8] + a[7] + a[6];
            int k3 = a[3] + a[4] + a[5] + a[6];
            if (k1 == k2 && k2 == k3) {
                res++;
            }

            return;
        }


        for (int i = 1; i <= 9; i++) {
            if (!st[i]) {
                a[u] = i;
                st[i] = true;
                dfs(u + 1);
                st[i] = false;
            }
        }
    }

    public static void main(String[] args) {
        dfs(0);
        System.out.println(res / 6);
    }
}

第八届省赛 java C组 填空题 与 java B组 填空题相同

第九届决赛 https://www.acwing.com/blog/content/51493/