Google Treasure Hunt 2008---Find the Smallest Prime Number

Question:
Find the smallest number that can be expressed as
the sum of 3 consecutive prime numbers,
the sum of 11 consecutive prime numbers,
the sum of 25 consecutive prime numbers,
the sum of 171 consecutive prime numbers,
the sum of 1225 consecutive prime numbers,
and is itself a prime number.


For example, 41 is the smallest prime number that can be expressed as
the sum of 3 consecutive primes (11 + 13 + 17 = 41) and
the sum of 6 consecutive primes (2 + 3 + 5 + 7 + 11 + 13 = 41).

Your answer:

My solution with VB6

  1. Dima(100000000)AsByte,p(10000000)AsLong,numAsLong,nAsLong
  2. SubGetprimes()
  3. Dimi&,j&,k
  4. p(0)=2'The1stprime
  5. k=10000'sqrarerootof10^8
  6. n=100000000'10^8
  7. Fori=3TokStep2
  8. Ifa(i)=0Then
  9. num=num+1
  10. p(num)=i
  11. Forj=i*iTonStep2*i'Eractosthenes
  12. a(j)=100'Notprimenumber
  13. Next
  14. EndIf
  15. Next
  16. Fori=k+1TonStep2'Listallprimenumberstoarrayp()
  17. Ifa(i)=0Then
  18. num=num+1
  19. p(num)=i
  20. EndIf
  21. Next
  22. EndSub
  23. PrivateSubCommand1_Click()
  24. DimsAsString,tmAsSingle
  25. s=InputBox("Pleaseenternumbers:","Info","3,11,25,171,1225")'Inputallnumbersthequestionhaslisted
  26. tm=Timer
  27. Getprimes
  28. s=minprime(s)
  29. tm=Timer-tm
  30. Clipboard.Clear
  31. Clipboard.SetTextCStr(s)'CopytheanswertoClipboard
  32. MsgBox"Itcostmeabout"&Format(tm,"0.0000")&"secondstofindtheanswer:"&s&vbCrLf&"Andithasbeencopiedtotheclipboard"
  33. EndSub
  34. Functionminprime(myprimesAsString)AsLong
  35. Dimi&,j&,sum()AsLong,countAsLong,primedata
  36. primedata=Split(myprimes,",")
  37. count=UBound(primedata)
  38. ReDimsum(count)
  39. Fori=0Tocount
  40. Forj=1Toprimedata(i)'Smallsumofcontinuousprimenumbers
  41. sum(i)=sum(i)+p(j)
  42. Next
  43. Ifa(sum(i))<100Thena(sum(i))=a(sum(i))+1'Meetoneoftheconditions
  44. Forj=primedata(i)+1Tonum
  45. sum(i)=sum(i)+p(j)-p(j-primedata(i))
  46. Ifsum(i)>nThenExitFor
  47. Ifa(sum(i))<100Thena(sum(i))=a(sum(i))+1'Meetoneoftheconditions
  48. Ifa(sum(i))=count+1Thenminprime=sum(i):ExitFunction'Meetalloftheconditions,Ok
  49. Next
  50. Next
  51. EndFunction

It returns:

6954293

你可能感兴趣的:(Google,J#)