备赛计挑

• 3210-2020-初赛-Java-1-3

import java.util.*;
import java.io.*;
 
 
class Main{
 
    static class Reader {
        static BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        static StringTokenizer tokenizer = new StringTokenizer("");
        static String next() throws IOException {// 读取下一个字符串
            while (!tokenizer.hasMoreTokens()) {
                tokenizer = new StringTokenizer(reader.readLine());
            }
            return tokenizer.nextToken();
        }
 
        static int nextInt() throws IOException {// 读取下一个int型数值
            return Integer.parseInt(next());
        }
    }
 
    public static void main(String[] args) throws IOException {
        int n = Reader.nextInt();
        int a = Reader.nextInt();
        int b =a-1;
        int count=0;
        for(int i=1;i<=n;i++){
            if(i%a==b&&i%2==0) count++;
        }
        System.out.println(count);
    }
}

• 3185-2020-Java-国赛-4-3

注意这里res要用long，不然要超

import java.util.*;
import java.io.*;
 
class Main{
 
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer tokenizer = new StringTokenizer(reader.readLine());
        // 获取到输入的字符串
        String input = tokenizer.nextToken();
        int[] prime;
        prime = new int[]{2,3,5,7,11,13,17,19,23,29};
        // 处理字符串
        int length = input.length();
        char[] chars=input.toCharArray();
        long temp,res=0;
        for(int i = length-1;i>=0;i--){
            if(chars[i]<='9') temp= chars[i]-=48;
            else temp=chars[i]-=87;
 
            for(int j=length-i-1;j>0;j--){
                temp*=prime[j-1];
            }
            res+=temp;
        }
        System.out.println(res);
 
    }
}