PAT第七题素数对猜想

题目很简单 我还是把我写的史山 写上去吧

import java.util.Scanner;
public class seven {
public static void main(String[] args) {Scanner myin = new Scanner(System.in);int n=myin.nextInt();int count=0;for(int i=2; i<=n ;i++){if(check(i)){count++;}}int arr[]=new int[count];for(int i=2,j=0; i<=n ;i++){if(check(i)){arr[j]=i;j++;}}int ans=0;for(int i=0; i<count-1 ;i++){if(arr[i+1]-arr[i]==2){ans++;}}System.out.println(ans);
}
public static boolean check(int a){
boolean con=true;
if(a<=1){con=false;
}
else{for(int i=2 ; i<=Math.sqrt(a);i++){if(a%i==0){con=false;break;}}
}
return con;}
}