「题目代码」P1007～P1012（Java）

1007 C基础-计负均正

import java.util.*;

import java.io.*;

public class Main

{

    public static void main(String args[])

    {

        Scanner sc=new Scanner(System.in);

        int x;

        int negativeCnt=0,positiveSum=0,zeroCnt=0;

        for(x=1;x<=20;++x)

        {

            int n=sc.nextInt();

            if(n<0) negativeCnt++;

            else if(n==0) zeroCnt++;

            else positiveSum+=n;

        }

        System.out.printf("%d\n%.2f",negativeCnt,positiveSum/(double)(20-negativeCnt-zeroCnt));

    }

}

1008 C基础-公约公倍

注意一下题干有问题，是空行不是空格。

 import java.util.*;

 import java.io.*;

 import java.math.BigInteger;

 public class Main

 {

     static int gcd(int x,int y)

     {

         if(y==0) return x;

         else return gcd(y,x%y);

     }

     static int lcm(int x, int y)

     {

         return x/gcd(x,y)*y;

     }

     public static void main(String args[])

     {

         Scanner cin=new Scanner(System.in);

         int n=cin.nextInt(),m=cin.nextInt();

         System.out.println(String.valueOf(gcd(n,m))+"\n"+String.valueOf(lcm(n,m)));

     }

 }

1009 C基础-统计字符

import java.util.*;

import java.io.*;

public class Main

{

    public static void main(String args[])

    {

        Scanner sc=new Scanner(System.in);

        String inputStr=sc.nextLine();

        int ch=0,sp=0,num=0,other=0;

        for(int i=0;i!=inputStr.length();++i)

        {

            if(Character.isDigit(inputStr.charAt(i)))

                num++;

            else if(Character.isLetter(inputStr.charAt(i)))

                ch++;

            else if(inputStr.charAt(i)==' ') sp++;

            else other++;

        }

        System.out.printf("%d\n%d\n%d\n%d\n",ch,sp,num,other);

    }

}

1010 C基础-阶乘数列

import java.util.*;

import java.io.*;

import java.math.BigInteger;

public class Main

{

    public static void main(String args[])

    {

        Scanner sc=new Scanner(System.in);

        BigInteger x=BigInteger.valueOf(0);

        for(int i=1;i<=30;++i)

        {

            BigInteger tmp=BigInteger.valueOf(1);

            for(int j=1;j<=i;++j)

            {

                tmp=tmp.multiply(BigInteger.valueOf(j));

                //System.out.println(tmp.toString()+" "+String.valueOf(j));

            }

            //System.out.println(tmp);

            x=x.add(tmp);

        }

        System.out.printf("%.2e",x.doubleValue());

    }

}

1011 C基础-进制转换

import java.util.*;

import java.io.*;

import java.math.BigInteger;

public class Main

{

    public static void main(String args[])

    {

        Scanner sc=new Scanner(System.in);

        int x=sc.nextInt();

        System.out.println(Integer.toOctalString(x));

    }

}

1012 SZ斐波拉契数列

保存计算结果以加快运算速度。注意每次清空。

import java.util.*;

import java.io.*;

import java.math.BigInteger;

public class Main

{

    static long[] arr=new long[35];

    static int a,b;

    public static void main(String args[])

    {

        Scanner sc=new Scanner(System.in);

        int T=sc.nextInt();

        while(T--!=0)

        {

            for(int i=0;i<=30;++i) arr[i]=0;

            a=sc.nextInt();

            b=sc.nextInt();

            int n=sc.nextInt();

            System.out.println(f(n));

        }

    }

    public static long f(int x)

    {

        //System.out.println(x);

        if(arr[x]!=0) return arr[x];

        else

        {

            if(x==1) arr[x]=a;

            else if(x==2) arr[x]=b;

            else if(x%2==1) arr[x]=f(x-1)+f(x-2);

            else arr[x]=f(x-1)+f(x-2)+f(x-3);

            return arr[x];

        }

    }

}