poj 3101 Astronomy

http://poj.org/problem?id=3101

这道题就是求所有分子的最小共倍数和分母的最大公约数。

 1 import java.math.BigInteger;

 2 import java.util.*;

 3 import java.util.Arrays;

 4 public class Main {

 5     public static void main(String []args)

 6     {

 7         Scanner cin=new Scanner(System.in);

 8         int n=cin.nextInt();

 9         int f2[]=new int[n];

10         BigInteger f[]=new BigInteger[2000];

11         BigInteger a[]=new BigInteger[2000];

12         BigInteger b[]=new BigInteger[2000];

13         BigInteger m1=new BigInteger("2");

14         for(int i=0; i<n; i++)

15         {

16             f2[i]=cin.nextInt();

17         }

18         Arrays.sort(f2);

19         int c=1;

20         f[0]=BigInteger.valueOf(f2[0]);

21         for(int i=1; i<n; i++)

22         {

23             if(f2[i]!=f2[i-1]) 

24             {

25                 f[c++]=BigInteger.valueOf(f2[i]);

26             }

27         }

28         int c1=0;

29         for(int i=1; i<c; i++)

30         {

31             a[c1]=(f[i].subtract(f[i-1])).multiply(m1);

32             b[c1]=f[i].multiply(f[i-1]);

33             BigInteger m=a[c1].gcd(b[c1]);

34             a[c1]=a[c1].divide(m);

35             b[c1]=b[c1].divide(m);

36             c1++;

37         }

38         BigInteger ans1=a[0];

39         BigInteger ans2=b[0];

40         BigInteger ans;

41         for(int i=1; i<c1; i++)

42         {

43             ans1=ans1.gcd(a[i]);

44             ans=ans2.multiply(b[i]);

45             ans2=ans.divide(ans2.gcd(b[i]));

46         }

47         ans=ans1.gcd(ans2);

48         System.out.println(ans2.divide(ans)+" "+ans1.divide(ans));

49         

50     }

51 }

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