HDU 4002 Find the maximum(欧拉函数)

题目链接

猜了一个结论，题面跟欧拉函数有关系。

import java.util.*;
import java.math.*;
import java.text.*;
import java.io.*;

public class Main {

    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        int p[] = new int[1001];
        int prim[] = new int[1001];
        int i, j, num, t;
        BigInteger n, temp;
        BigInteger s[] = new BigInteger[201];
        num = 0;
        for (i = 0; i <= 1000; i++)
            p[i] = 0;
        for (i = 2; i <= 1000; i++) {
            if (p[i] == 0) {
                prim[num++] = i;
                for (j = i + i; j <= 1000; j += i) {
                    p[j] = 1;
                }
            }
        }
        s[0] = BigInteger.valueOf(prim[0]);
        for (i = 1; i < 150; i++) {
            temp = BigInteger.valueOf(prim[i]);
            s[i] = s[i - 1].multiply(temp);
            
        }
        t = cin.nextInt();
        while (t > 0) {
            n = cin.nextBigInteger();
            for (i = 1; i < num; i++) {
                if (n.compareTo(s[i]) == -1) {
                    break;
                }
            }
            System.out.println(s[i-1]);
            t--;
        }
    }
}