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  1. import java.math.BigInteger;
  2. class Ideone{
  3.   static final int c11=25,c23=30;
  4.   static final int b11=(1<<c11)-1,b23=(1<<c23)-1;
  5.   static BigInteger i2b(int[]a){
  6.     return BigInteger.valueOf((long)a[2])
  7.       .add(BigInteger.valueOf((long)a[1]).shiftLeft(c23))
  8.       .add(BigInteger.valueOf((long)a[0]).shiftLeft(c23+c23));
  9.   }
  10.   static int[] add(int[]a,int[]b){
  11.     int[]c={0,0,0}; int z=0;
  12.     z+=a[2]+b[2]; c[2]=z&b23; z>>=c23;
  13.     z+=a[1]+b[1]; c[1]=z&b23; z>>=c23;
  14.     z+=a[0]+b[0]; c[0]=z&b11;
  15.     return c;
  16.   }
  17.   static int[] mul(int[]a,int[]b){
  18.     int[]c={0,0,0}; long z=0L;
  19.     z+=(long)a[2]*(long)b[2];
  20.     c[2]=(int)(z&(long)b23); z>>=(long)c23;
  21.     z+=(long)a[1]*(long)b[2]+(long)a[2]*(long)b[1];
  22.     c[1]=(int)(z&(long)b23); z>>=(long)c23;
  23.     z+=(long)a[0]*(long)b[2]+(long)a[1]*(long)b[1]+(long)a[2]*(long)b[0];
  24.     c[0]=(int)(z&(long)b11);
  25.     return c;
  26.   }
  27.   public static void main(String[] args){
  28.     int[] b={0,0, 2};
  29.     int[] a={0,0,27};
  30.     int[] s={0,0,27};
  31.     int[] t;
  32.     long ms0 = System.currentTimeMillis();
  33.     for (long i = 1L; i < 1099511627776L/30000L ; i++){
  34.       t = mul(a,a); a = mul(t,a); s = add(s,a);
  35.     }
  36.     long ms = System.currentTimeMillis()-ms0;
  37.     System.out.println(i2b(s)+"/"+ms);
  38.     System.out.println("1099511627776L => "+30000d*ms/(1000*60*60*24));
  39.   }
  40. }
Success #stdin #stdout 0.56s 2184192KB
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Standard input is empty
stdout
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17396612018432151008312873/511
1099511627776L => 0.17743055555555556
https://ideone.com/Tc4Wjc
language:
Java (HotSpot 12)
created:
6 years ago
visibility:
secret

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