POJ 2635 The Embarrassed Cryptographer(JAVA)

题目链接

本来想用java 偷懒的。。。结果。。。浪费了3个小时，血的教训啊BigInteger不能用== 来判断。。。用compareTo 或者equals来判断是否相同，我在本地对拍的好久，没拍出错来，然后最后实在是没办法了，从网上找JAVA代码。。。在晒代码里，找到一份，然后一行一行的比对。。。终于，过了。。

 1 import java.io.*;
 2 import java.math.*;
 3 import java.text.*;
 4 import java.util.*;
 5 public class Main 
 6 {
 7     public static void main(String[] args)
 8     {
 9         BigInteger n,zero,temp;
10         Scanner cin = new Scanner(System.in);
11         int []o = new int [1000101];
12         int []prime = new int [100000];
13         int i,j,k,N,num = 0,z;
14         N = 1000100;
15         zero = BigInteger.valueOf(0);
16         for(i = 2;i <= N;i ++)
17             o[i] = 0;
18         for(i = 2;i <= N;i ++)
19         {
20             if(o[i] == 0)
21             {
22                 for(j = i+i;j <= N;j += i)
23                 o[j] = 1;
24             }
25         }
26         for(i = 2;i <= N;i ++)
27         {
28         if(o[i] == 0)
29             prime[++num] = i;
30         }
31         while(cin.hasNext())
32         {
33             n = cin.nextBigInteger();
34             k = cin.nextInt();
35             if(k == 0&&n.compareTo(zero) == 0)
36                 break;
37             z = 1;
38             for(i = 1;i <= num;i ++)
39             {
40                 if(prime[i] >= k)
41                 {
42                     break;
43                 }
44                 temp = BigInteger.valueOf(prime[i]);
45                 if(n.mod(temp).compareTo(zero) == 0)
46                 {
47                     z = 0;
48                     System.out.println("BAD "+prime[i]);
49                     break;
50                 }
51             }
52             if(z == 1)
53                 System.out.println("GOOD");
54         }    
55     }
56 }

 

posted @ 2013-01-23 16:03  Naix_x  阅读(224)  评论(0)  编辑  收藏  举报