2018 焦作E java 高精度暴力
https://vjudge.net/problem/Gym-102028E
暴力,线性递推分母
//package acm; import java.math.BigInteger; import java.util.Scanner; import com.sun.org.apache.bcel.internal.generic.SWAP; import com.sun.org.apache.bcel.internal.generic.StackConsumer; import sun.management.GcInfoCompositeData; public class Main{ public static final int maxn=1000,maxm=200000; public static BigInteger gcd(BigInteger a,BigInteger b) { if(b.compareTo(BigInteger.ZERO)==0)return a; else return gcd(b, a.remainder(b)); } public static void main(String[] argc){ int[]a=new int[maxn]; for(int i=2;i<maxn;i++) a[i]=i; for(int i=2;i<maxn;i++) if(a[i]!=0) for(int j=i*2;j<maxn;j=j+i) a[j]=0; Scanner cin=new Scanner(System.in); int casn=cin.nextInt(); int[] prime=new int[10000]; for(int ii=1;ii<=casn;++ii) { BigInteger x=cin.nextBigInteger(); BigInteger res=BigInteger.ONE; BigInteger now=BigInteger.ONE; int i=1; while(true) { i++; if(a[i]==0) continue; if(res.multiply(BigInteger.valueOf(a[i])).compareTo(x)<=0) { res=res.multiply(BigInteger.valueOf(a[i])); now=now.multiply(BigInteger.valueOf(a[i]+1)); }else break; } BigInteger g=gcd(res,now); res=res.divide(g); now=now.divide(g); System.out.println(res+"/"+now); } } }