answer for 質數問題

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Steven_Tian

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Nov 16, 2010, 8:41:53 AM11/16/10
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//用你原本的寫法很難寫,所以全部改成我自己的寫法,你可以參考觀念改成你自己的寫法
import java.util.ArrayList;

public class test {
public static ArrayList isPrime(int numbers) {
ArrayList al=new ArrayList();
boolean b = false;
for(int i=2;i<numbers;i++){
if (i % 2 != 0 && i % 3 != 0 && i % 5 != 0 && i % 7 != 0 || i == 2
|| i == 3 || i == 5 || i == 7) {
al.add(i);
}
}

for(int i=0;i<al.size();i++){
int exp=2;
int base=(Integer)al.get(i);
for(;exp <14;exp++){
al.remove(Integer.valueOf((int)Math.pow(base, exp)));
}
}

return al;
}
public static void main(String args[]) {
ArrayList al=isPrime(10000);
System.out.println("質數共有");
System.out.println(al.size());
System.out.println(al.toString());
System.out.println("個");
}

}



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