第十届蓝桥杯Java B组

试题B

答案：100

注意Java的substring的两个参数为起始的下标和结尾的下标+1，所以j = i + 1防止出现空字符串

import java.math.*;
import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = "0100110001010001";
        int len = s.length();
        Set<String> se = new HashSet<>();
        for(int i = 0; i < len; i++)
        {
            for(int j = i + 1; j <= len; j++)
            {
                String tmp = s.substring(i, j);
                se.add(tmp);
            }
        }
        System.out.println(se.size());
    }
}

试题C

答案：4659

import java.math.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[] a = new int[30000000];
        a[1] = 1; a[2] = 1; a[3] = 1;
        for(int i = 4; i <= 20190324; i++)
        {
            a[i] = ((a[i-1] + a[i-2])%10000 + a[i-3])%10000;
        }
        System.out.println(a[20190324]);
    }
}

试题D

答案：40785

import java.math.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int ans = 0;
        for(int i = 1; i <= 2019; i++)
        {
            for(int j = i + 1; j <= 2019; j++)
            {
                for(int k = j + 1; k <= 2019; k++)
                if(check(i) && check(j) && check(k) && (i + j + k) == 2019) 
                    ans++;
            }
        }
        System.out.println(ans);
    }
    public static boolean check(int x)
    {
        while(x > 0)
        {
            if(x % 10 == 2 || x % 10 == 4) return false;
            x /= 10;
        }
        return true;
    }
} 

试题E

答案

DDDDRRURRRRRRDRRRRDDDLDDRDDDDDDDDDDDDRDDRRRURRUURRDDDDRDRRRRRRDRRURRDDDRRRRUURUUUUUUULULLUUUURRRRUULLLUUUULLUUULUURRURRURURRRDDRRRRRDDRRDDLLLDDRRDDRDDLDDDLLDDLLLDLDDDLDDRRRRRRRRRDDDDDDRR

import java.math.*;
import java.util.*;

class node
{
    int x,y;
    String ans;
    node(int x,int y, String ans)
    {
        this.x = x;
        this.y = y;
        this.ans = ans;
    }
}

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = "01010101001011001001010110010110100100001000101010"
                + "00001000100000101010010000100000001001100110100101"
                + "01111011010010001000001101001011100011000000010000"
                + "01000000001010100011010000101000001010101011001011"
                + "00011111000000101000010010100010100000101100000000"
                + "11001000110101000010101100011010011010101011110111"
                + "00011011010101001001001010000001000101001110000000"
                + "10100000101000100110101010111110011000010000111010"
                + "00111000001010100001100010000001000101001100001001"
                + "11000110100001110010001001010101010101010001101000"
                + "00010000100100000101001010101110100010101010000101"
                + "11100100101001001000010000010101010100100100010100"
                + "00000010000000101011001111010001100000101010100011"
                + "10101010011100001000011000010110011110110100001000"
                + "10101010100001101010100101000010100000111011101001"
                + "10000000101100010000101100101101001011100000000100"
                + "10101001000000010100100001000100000100011110101001"
                + "00101001010101101001010100011010101101110000110101"
                + "11001010000100001100000010100101000001000111000010"
                + "00001000110000110101101000000100101001001000011101"
                + "10100101000101000000001110110010110101101010100001"
                + "00101000010000110101010000100010001001000100010101"
                + "10100001000110010001000010101001010101011111010010"
                + "00000100101000000110010100101001000001000000000010"
                + "11010000001001110111001001000011101001011011101000"
                + "00000110100010001000100000001000011101000000110011"
                + "10101000101000100010001111100010101001010000001000"
                + "10000010100101001010110000000100101010001011101000"
                + "00111100001000010000000110111000000001000000001011"
                + "10000001100111010111010001000110111010101101111000";
        int[][] a = new int[30][50];
        int[][] vis = new int[30][50];
        int len = s.length();
        for(int i = 0; i < len; i++)
        {
            a[i/50][i%50] = s.charAt(i) - '0';
        }
        String ans = "";
        int x = 0, y = 0;
        vis[0][0] = 1;
        int[][] k = {{1, 0}, {0, -1}, {0, 1}, {-1, 0}};
        node tmp = new node(0, 0 , "");
        Queue<node> q= new LinkedList<>();
        q.offer(tmp);
        while(!q.isEmpty())
        {
            node t = q.poll();
            if(t.x == 29 && t.y == 49)
            {
                System.out.println(t.ans);
                break;
            }
            for(int i = 0; i <= 3; i++)
            {
                int tmpx = t.x + k[i][0], tmpy = t.y + k[i][1];
                if(tmpx >= 0 && tmpx < 30 && tmpy >= 0 && tmpy < 50 && vis[tmpx][tmpy] == 0 && a[tmpx][tmpy] == 0)
                {
                    vis[tmpx][tmpy] = 1;
                    String st = t.ans;
                    if(i == 0) st += 'D';
                    if(i == 1) st += 'L';
                    if(i == 2) st += 'R';
                    if(i == 3) st += 'U';
                    node t2 = new node(tmpx, tmpy, st);
                    q.offer(t2);
                }
            }
        }
    }
} 

试题F

import java.math.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int ans = 0;
        for(int i = 1; i <= n; i++)
        {
            if(check(i)) ans += i;
        }
        System.out.println(ans);
    }
    public static boolean check(int x)
    {
        while(x > 0)
        {
            if(x % 10 == 2 || x % 10 == 0 || x % 10 == 1 || x % 10 == 9) 
                return true;
            x /= 10;
        }
        return false;
    }
} 

试题G

import java.math.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Map<Integer, List<Integer>> mp = new HashMap<>();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int t = sc.nextInt();
        int[] sum = new int[n+1];
        int[] cnt = new int[n+1];
        for(int i = 0; i < m; i++)
        {
            int tmpt = sc.nextInt();
            int tmpid = sc.nextInt();
            if(mp.get(tmpt) == null)
            {
                List<Integer> tmpl = new ArrayList<>();
                tmpl.add(tmpid);
                mp.put(tmpt, tmpl);
            }
            else 
                mp.get(tmpt).add(tmpid);
        }
        int last = 0, ans = 0;
        for(Integer key : mp.keySet())
        {
            int key1 = key;
            List<Integer> tmpL = mp.get(key1);
            int[] vis = new int[n+1];
            int timespan = key1 - last;
            for(int j : tmpL) vis[j] += 1;
            for(int j = 1; j <= n; j++)
            {
                if(vis[j] > 0) sum[j] += 2 * vis[j];
                else sum[j] = sum[j] - timespan < 0 ? 0 : sum[j] - timespan;
                if(sum[j] > 5)
                    cnt[j] = 1;
                else if(sum[j] <= 3)
                    cnt[j] = 0;
            }
            last = key1;
        }
        for(int i = 1; i <= n; i++)
        {
            int timespan = t - last;
            sum[i] = sum[i] - timespan < 0 ? 0 : sum[i] - timespan;
            if(sum[i] <= 3)
                cnt[i] = 0;
        }
        for(int i = 1; i <= n; i++)
        {
            if(cnt[i] == 1)
                ans++;
        }
        System.out.println(ans);
    }
} 

试题H

import java.math.*;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int K = sc.nextInt();
        sc.nextLine();
        String s = sc.nextLine();
        String[] word = s.split("\s+|\.");
        int len = word.length;
        int ans = 0;
        for(int i = 0; i < len; i++)
        {
            if(word[i].equals("Alice"))
            {
                for(int j = i + 1; j < len; j++)
                {
                    if(word[j].equals("Bob"))
                    {
                        int L = 1;
                        for(int k = i + 1; k < j; k++) 
                            L += (1 + word[k].length());
                        if(L <= K) ans++;
                    }
                }
            }
        }
        for(int i = 0; i < len; i++)
        {
            if(word[i].equals("Bob"))
            {
                for(int j = i + 1; j < len; j++)
                {
                    if(word[j].equals("Alice"))
                    {
                        int L = 1;
                        for(int k = i + 1; k < j; k++)
                            L += (1 + word[k].length());
                        if(L <= K) ans++;
                    }
                }
            }
        }
        System.out.println(ans);
    }
}