求第100002个素数。（2是第一个素数）
结题思路：素数筛法
代码如下：
import java.util.Arrays;
public class Copy_2_of_Main {
static int N = 10000000; static int count; static int rs[] = new int[N]; static boolean tg[] = new boolean[N];//is prime 
public static void main(String[] args) {
Arrays.fill(tg, true); int ed = (int)Math.sqrt(N) + 1; for(int i = 2; i <= ed; i++){//素数筛法 if(tg[i]){ for(int j = i * 2; j < N; j += i){// j += i tg[j] = false;
} } } count = 0; for(int i = 2; i < N; i++){ if(tg[i] == true){ rs[count++] = i; } } System.out.println("count=" + count); System.out.println("result=" + rs[100001]);// for(int i = 0; i < count; i++)// System.out.println(rs[i]); } 
}