第十四届蓝桥杯三月真题刷题训练——第 26 天

目录

第 1 题：玩具

代码：

第 2 题：滑雪_dfs

代码：

第 3 题：abb_后缀和

代码：

第 4 题：小红取数_dp

代码：

---

第 1 题：玩具

 

代码：

package 第十四届蓝桥杯三月真题刷题训练.day26;

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

/**
 * @author yx
 * @date 2023-03-29 18:37
 */
public class 玩具 {
    static PrintWriter out =new PrintWriter(System.out);
    static BufferedReader ins=new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer in=new StreamTokenizer(ins);
    /**
     * 输入
     * in.nextToken()
     * int a= (int)in.nval;
     *
     * 输出
     * out.print();
     * out.flush();
     *
     * 读文件：
     * BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("C:\\Users\\yx\\Desktop\\primes.txt")));
     * String s = br.readLine();s读取每一行数据
     * if (s == null)break;读取文件终止的语句
     **/
    public static void main(String[] args) throws IOException {
        in.nextToken();
        int N=(int) in.nval;
        long[] nums=new long[N];
        String[] strings=ins.readLine().split(" ");
        for (int i = 0; i < N; i++) {
            nums[i]=Long.parseLong(strings[i]);
        }
        Arrays.sort(nums);
        long ans=0;
        for (int i = N-1; i >=0 ; i-=2) {
            ans+=nums[i];
        }
        out.println(ans);
        out.flush();
    }
}

第 2 题：滑雪_dfs

 

代码：

package 第十四届蓝桥杯三月真题刷题训练.day26;

import java.io.*;

/**
 * @author yx
 * @date 2023-03-29 18:46
 */
public class 滑雪_记忆化搜索 {
    static PrintWriter out =new PrintWriter(System.out);
    static BufferedReader ins=new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer in=new StreamTokenizer(ins);
    static int ans=0;
    static boolean[][] isTrue;
    static int[] X={0,0,-1,1};
    static int[] Y={1,-1,0,0};
    static int[][] nums;
    static int n;
    static int m;
    /**
     * 输入
     * in.nextToken()
     * int a= (int)in.nval;
     *
     * 输出
     * out.print();
     * out.flush();
     *
     * 读文件：
     * BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("C:\\Users\\yx\\Desktop\\primes.txt")));
     * String s = br.readLine();s读取每一行数据
     * if (s == null)break;读取文件终止的语句
     **/

    public static void main(String[] args) throws IOException {
        in.nextToken();
        n=(int) in.nval;
        in.nextToken();
        m=(int) in.nval;
        nums=new int[n][m];
        isTrue=new boolean[n][m];
        String[] strings=new String[n];
        for (int i = 0; i < n; i++) {
            strings[i]=ins.readLine();
        }
        for (int i = 0; i < n; i++) {
            String[] strings1=strings[i].split(" ");
            for (int j = 0; j < m; j++) {
                nums[i][j]=Integer.parseInt(strings1[j]);
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                dfs(i,j,1);
            }
        }
        out.println(ans);
        out.flush();
    }
    static void dfs(int i,int j,int cnt){
        ans=Math.max(ans,cnt);
        //表示这个地方搜过了
        isTrue[i][j]=true;
        for (int k = 0; k < 4; k++) {
            int newX=i+X[k];
            int newY=j+Y[k];
            if(newX>=0&&newY>=0&&newXnums[newX][newY]&&!isTrue[newX][newY]){
                dfs(newX,newY,cnt+1);//步数+1
            }
        }
        //回溯
        isTrue[i][j]=false;
    }
}

第 3 题：abb_后缀和

 

代码：

package 第十四届蓝桥杯三月真题刷题训练.day26;

import java.io.*;

/**
 * @author yx
 * @date 2023-03-29 19:16
 */
public class abb_后缀和_long {
    static PrintWriter out =new PrintWriter(System.out);
    static BufferedReader ins=new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer in=new StreamTokenizer(ins);
    /**
     * 输入
     * in.nextToken()
     * int a= (int)in.nval;
     *
     * 输出
     * out.print();
     * out.flush();
     *
     * 读文件：
     * BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("C:\\Users\\yx\\Desktop\\primes.txt")));
     * String s = br.readLine();s读取每一行数据
     * if (s == null)break;读取文件终止的语句
     **/
    public static void main(String[] args) throws IOException {
        in.nextToken();
        int length=(int) in.nval;
        char[] arrays=ins.readLine().toCharArray();
        int[][] nums=new int[length+1][26];
        char temp=' ';
        long ans=0;
        for (int i = length-1; i >= 0; i--) {
            //先对上一组全部备份
            for (int j = 0; j < 26; j++) {
                nums[i][j]=nums[i+1][j];
            }
            temp=arrays[i];
            //在上一份的基础上进行++
            nums[i][temp-'a']++;
        }
        for (int i = 0; i < length; i++) {
            for (int j = 0; j < 26; j++) {
                if(j!=arrays[i]-'a'){
                    ans+=(long) (nums[i][j])*(nums[i][j]-1)/2;
                }
            }
        }
        out.println(ans);
        out.flush();
    }
}

第 4 题：小红取数_dp

 

代码：

package 第十四届蓝桥杯三月真题刷题训练.day26;

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

/**
 * @author yx
 * @date 2023-03-29 19:50
 */
public class 小红取数_dp {
    static PrintWriter out =new PrintWriter(System.out);
    static BufferedReader ins=new BufferedReader(new InputStreamReader(System.in));
    static StreamTokenizer in=new StreamTokenizer(ins);
    /**
     * 输入
     * in.nextToken()
     * int a= (int)in.nval;
     *
     * 输出
     * out.print();
     * out.flush();
     *
     * 读文件：
     * BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream("C:\\Users\\yx\\Desktop\\primes.txt")));
     * String s = br.readLine();s读取每一行数据
     * if (s == null)break;读取文件终止的语句
     **/
    public static void main(String[] args) throws IOException {
        in.nextToken();
        int n=(int) in.nval;
        in.nextToken();
        int k=(int) in.nval;
        long[][]dp=new long[n+1][k];
        long[] nums=new long[n+1];
        String[] strings=ins.readLine().split(" ");
        for (int i = 0; i <= n; i++) {
            Arrays.fill(dp[i],Long.MIN_VALUE);
        }
        for (int i = 0; i < n; i++) {
            nums[i+1]=Long.parseLong(strings[i]);
        }
        dp[0][0]=0;
        for (int i = 1; i <= n; i++) {
            for (int j = 0; j < k; j++) {
                //无敌的状态转移方程
                dp[i][(int)((nums[i]+j)%k)]=Math.max(dp[i-1][j]+nums[i],dp[i-1][(int)((nums[i]+j)%k)]);
            }
        }
//        for (int i = 0; i <= n ; i++) {
//            for (int j = 0; j < k; j++) {
//                System.out.print(dp[i][j]+" ");
//            }
//            System.out.println();
//        }
        if(dp[n][0]>0)out.println(dp[n][0]);
        else out.println(-1);
        out.flush();
    }
/*
0 -1 -1 -1 -1
7 7 7 8 7
10 9 9 9 9
18 18 18 18 19
20 19 19 19 19
20 19 19 19 19
20
*/

/*
0 0 0 0 0
8 8 8 8 8
10 10 10 10 10
19 19 19 19 19
20 20 20 20 20
20 20 20 20 20
20
*/
}