## Computer Networks

Computer Networks. Part One: LANs and WANs Computer Networks. Part Two: Network Hardware Computer Networks. Part Three: Ethernet Fundamentals Computer Networks. Part Four: LAN Topology Computer Networks. Part Five: Switched Ethernet LANs Computer Networks. Part Six: The TCP/IP Protocol Stack and Routers Domain Name System DNS

## Permutation and Combination

Permutation – position (order) matters. = N! / (N – r)!. Building words with {a,b,c} are also permutation problem with r = {1,2,3..N} Combination – position (order) doesn’t matter = N! / (N – r)! * r! . Combination is a part of Permutation set. All possible combination means, generating combination for r = {0,1.. […]

## Binary Left Shift << and Right Shift >>

Binary Left Shift << When shifting left, the most-significant bit is lost, and a 0 bit is inserted on the right end. Left shift is equivalent to multiplying the bit pattern by 2k (if we are shifting k bits). 10 << 2  = 10 * 22 = 10 * 4 = 40 10 << 3 = 10 […]