LUCAS THEOREM !

For nCk;
  nCk % p = ((a1Cb1)*(a2Cb2)*..............*(anCbn)) % p
where a1,a2,a3..... are digits in base-p representation of n &
where b1,b2,b3..... are digits in base-p representation of k. 

For nCr ;

No. of terms divisible in the nCk by a prime no. p may be equal to the :
        (a1+1)*(a2+1)*(a3+1).............. (am+1)   
where a1,a2,a3,...am are the digits in base p representaion (a1a2....am)base p 

Special case of this is the Odd numbers in nCk (i.e row of pascal triangle)


Link to problems:
1) http://www.spoj.com/problems/DUKKAR/
2) http://www.spoj.com/problems/HLP_RAMS/
3) http://www.spoj.com/problems/AJOB/

KALI LINUX : BACKTRACK REBORN

MOST ADVANCED PENETRATION DISTRIBUTIOON EVER!!!

Kali Linux is a Debian-derived Linux distribution designed for digital forensics and penetration testing. It is maintained and funded by Offensive Security Ltd. It was developed by Mati Aharoni and Devon Kearns of Offensive Security through the rewrite of BackTrack, their previous forensics Linux distribution.
Kali Linux is preinstalled with numerous penetration-testing programs, including nmap (a port scanner), Wireshark (apacket analyzer), John the Ripper (a password cracker), Aircracking (a software suite for penetration-testing wireless LANs), Burp suite and OWASP ZAP (both web application security scanners).