Hello Java
第一次使用Java还有很多生疏的地方 仅作为记录。 </br>
题目比较简单所以代码也比较生猛~ </br>
顺便练习一下m语法以及git </br>
git add 2018-08-14-HelloJava.md</br>
git commit -m “想说啥就说点啥吧”</br>
git push origin master
题目
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#一
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#二
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#三
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#四
T1大整数加法
高精度加法，还记得数据结构第一次作业的第一题就是高精度乘法，
所以这题没什么难度,用来熟悉JAVA还好。
import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
Scanner scan = new Scanner (System.in);
while(scan.hasNext())
{
String num1=new String() ;
String num2=new String() ;
num1=scan.next();// save num1 as String
num2=scan.next();
int len1=num1.length();
int len2=num2.length();
int [] n1=new int[5001];
int [] n2=new int[5001];
int [] ans=new int[5001];
for(int i=0;i<len1;i++)//solve number1
{
char data=num1.charAt(i);
if(data>='0'&&data<='9')
{
n1[len1-i-1]=(int)data-'0';
}
}
for(int i=0;i<len2;i++)//solve number2
{
char data=num2.charAt(i);
if(data>='0'&&data<='9')
{
n2[len2-i-1]=(int)data-'0';
}
}
int maxlen=0;
if(len1>len2)
maxlen=len1;
else
maxlen=len2;
int sign=0;
for(int i=0;i<maxlen;i++)
{
if(sign==1)
{
int temp=n1[i]+n2[i]+1;
if(temp>=10)
{
sign=1;
temp=temp%10;
}
else
sign=0;
ans[i]=temp;
}
else
{
int temp=n1[i]+n2[i];
if(temp>=10)
{
sign=1;
temp=temp%10;
}
else
sign=0;
ans[i]=temp;
}
}
if(sign==1)
{
maxlen=maxlen+1;
ans[maxlen-1]=1;
}
for(int i=maxlen-1;i>=0;i--)
{
System.out.print(ans[i]);
}
System.out.print("\n");
}
scan.close();
}
}
T2挑选最小的质数
筛出质数&&排序也没什么可说的，这道题是最先开始写的一道，熟悉了JAVA的一些操作之后就很简单了。
package hellotest;
import java.util.Scanner;
import java.util.Arrays;
public class helloworld1 {
public static void main(String[] args)
{
// TODO Auto-generated method stub
Scanner scan = new Scanner (System.in);
while(scan.hasNextInt())
{
int M=scan.nextInt();//M
int N=scan.nextInt();//N
int[] numbers=new int[M];
int[] primes=new int [N];
for (int i=0;i<M;i++)
{
numbers[i]=scan.nextInt();
// System.out.println(numbers[i]);
}
Arrays.sort(numbers);//SORT
int numberOfPrimes=0;
for(int i=0;i<M;i++)
{
if(NumberIsPrime(numbers[i]))
{
primes[numberOfPrimes++]=numbers[i];
}
}
if(primes[N-1]!=0)
System.out.println(primes[N-1]);
else
System.out.println(-1);
}
scan.close();
}
private static boolean NumberIsPrime(int n)//judge the number is prime
{
if(n==1)
return false;
for(int i=2;i<n;i++)
{
if(n%i==0)
return false;
}
return true;
}
}
T3矩阵相乘
我觉得这道是最简单的一个，不说了。
import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
int row1=scan.nextInt();
int col1=scan.nextInt();
int [][]matrix1=new int[row1][col1];
for(int i=0;i<row1;i++)
{
for(int j=0;j<col1;j++)
{
matrix1[i][j]=scan.nextInt();
}
}
int row2=scan.nextInt();
int col2=scan.nextInt();
int [][]matrix2=new int[row2][col2];
for(int i=0;i<row2;i++)
{
for(int j=0;j<col2;j++)
{
matrix2[i][j]=scan.nextInt();
}
}
scan.close();
int [][]ans=new int[row1][col2];
for(int i=0;i<row1;i++)
{
for(int j=0;j<col2;j++)
{
ans[i][j]=getAns(i,j,row1,col1,row2,col2,matrix1,matrix2);
//System.out.println(ans[i][j]);
}
}
for(int i=0;i<row1;i++)
{
for(int j=0;j<col2;j++)
{
System.out.print(ans[i][j]);
if(i==row1-1&&j==col2-1) {}
else
System.out.print(" ");
}
System.out.print("\n");
}
}
private static int getAns(int row,int col,int row1,int col1,int row2,int col2,int m1[][],int m2[][])
{
int data=0;
for(int i=0;i<col1;i++)
{
data=m1[row][i]*m2[i][col]+data;
}
return data;
}
}
T4合法标识符
这道题首先要了解java的合法标识符是什么。
对开头符号的要求以及中间符号的要求，最后再检查一下是否和保留字冲突就ok。对于关键字……emmmmmm就直接**暴力**吧 代码就很暴力
import java.util.Arrays;
import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
Scanner scan=new Scanner(System.in);
String data=new String();
data=scan.next();
scan.close();
System.out.print(judge(data));
}
private static int judge(String temp)
{
String[] key= {"abstract","assert", "boolean","break","byte",
"case","catch","char","class","const","continue","default","do","double","else",
"enum","extends" ,"final" ,"finally" ,"float",
"for", "goto","if","implements","import",
"instanceof","int","interface","long","native",
"new","package","private","protected","public",
"return","strictfp","short","static","super",
"switch","synchronized","this","throw","throws",
"transient" ,"try" ,"void" ,"volatile" ,"while"};
if(temp.length()==0||!Character.isJavaIdentifierStart(temp.charAt(0)))
{
return -1;
}
String tempTail=temp.substring(1);
for(int i=0;i<tempTail.length();i++)
{
if(!Character.isJavaIdentifierPart(tempTail.charAt(i)))
{
return -1;
}
}
boolean flag=Arrays.asList(key).contains(temp);
if(flag==true)
return -1;
return 0;
}
}
what’s more
` 首先感谢教授提供美艳封面照片 `
刚刚教授吃饭的时候准备起诉我侵犯他的肖像权
emm教授最帅了封面是教授手拿体校通知书的稚嫩照
写这篇主要是学习一下git以及记录一下昨天刚开始学的JAVA，git前面看过一些教程，今天才算正式git push，至于markdown，其实我现在都还不知道到底怎么换行！！！前面用了html的换行发现在markdownpad这里是ok的，但是在github上又崩了，溜了溜了踢球去了。
