4002 大数 java

打素数表

import java.util.*;
import java.io.*;
import java.math.*;
public class Main
{
	static int[] pri=new int[1000];
	static int len=0,anslen;
	static BigInteger n,up,temp;
	static boolean[] vis=new boolean[1000];
	static BigInteger[] ans=new BigInteger[1000]; 
	static
	{
		up=BigInteger.valueOf(1);
		for(int i=0;i<100;i++)
		{
				up=up.multiply(BigInteger.valueOf(10));
			}
		len=0;
			for(int i=2;i<1000;i++)
			{
					if(!vis[i]) pri[len++]=i;
					for(int j=0;j<len&&i*pri[j]<1000;j++)
					{
						vis[i*pri[j]]=true;
						if(i%pri[j]==0) break;
					}
			}
					anslen=-1;
			ans[++anslen]=BigInteger.valueOf(1);
			do
			{
				anslen++;
				temp=ans[anslen]=ans[anslen-1].multiply(BigInteger.valueOf(pri[anslen-1]));
				}while(temp.compareto(up)<0);
	}
		public static void main(String args[])
		{
				Scanner cin=new Scanner(new BufferedInputStream(system.in));
				while(cin.hasNext())
				{
					int t=cin.nextInt();
					for(int j=0;j<t;j++)
					{
						n=cin.nextBigInteger();
						for(int i=0;i<anslen;i++)
						{
								if(n.compareto(ans[i])>=0) temp=ans[i];
							}
							System.out.println(temp);
					}
				}
		}
	}