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  1. /* package whatever; // don't place package name! */
  2.  
  3. import java.util.*;
  4. import java.lang.*;
  5. import java.io.*;
  6. import java.math.*;
  7.  
  8. /* Name of the class has to be "Main" only if the class is public. */
  9. class Ideone
  10. {
  11. public static void main (String[] args) throws java.lang.Exception
  12. {
  13. System.out.println(getCollisionProbability(23, 365));
  14. }
  15.  
  16. static BigDecimal getCollisionProbability(int n, int p){
  17. return (new BigDecimal("1")).subtract(fact(p).divide((new BigDecimal(String.valueOf(p))).pow(n).multiply(fact(p-n)), 6, RoundingMode.HALF_UP));
  18. }
  19.  
  20. static BigDecimal fact(int n){
  21. if (n==1) return BigDecimal.ONE; else return fact(n-1).multiply(new BigDecimal(String.valueOf(n)));
  22. }
  23. }
Success #stdin #stdout 0.14s 321024KB
stdin
Standard input is empty
stdout
0.507297