数素数

 

//需要注意两点：一是Pm和Pn表示的是素数个数的区间，而不是在这两个数范围内找素数；

//二是输出情况分三种，首先是未满10个数一行的中间每个数输出中间都有空格，再者是满10个数时要进行换行                       // 操作，最后是输出的最后一个数如果不是在输出行的第十个数，则其后面不能有空格。

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import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader;   public class Main {     public static void main(String[] args) throws IOException{         BufferedReader br=new BufferedReader(new InputStreamReader(System.in));         String str=br.readLine();         String[] s1=str.split(" ");         int Pm=Integer.parseInt(s1[0]);         int Pn=Integer.parseInt(s1[1]);         int count1=1;//计数素数个数         int count2=1;//计数素数数是否为10个         boolean flag;         for(int i=2;count1<=Pn;i++){             if(flag=isPrime(i) && count1<Pm){                 count1++;                 continue;             }             if(flag=isPrime(i)){                 if(count2%10!=0 && count1!=Pn){                     System.out.print(i+" ");                     count2++;                     count1++;                 }else if(count2%10==0 && count1!=Pn){                     System.out.println(i);                     count2=1;                     count1++;                                   }else if(count2%10!=0 && count1==Pn){                     System.out.print(i);                     count1++;                     count2++;                 }             }                                       }     }           private static boolean isPrime(int num) {                   boolean flag=true;         if(num<2)             return false;         else{             for(int i=2;i<=Math.sqrt(num);i++){                 if(num%i==0){                     flag=false;                     break;                 }             }                   }         return flag;     }   }

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