Emiliano Firmino Miliox

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be a both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth. It also will be available as a gist on Github for everyone to edit and add to.

Data Structure Basics

###Array ####Definition:

Stores data elements based on an sequential, most commonly 0 based, index.
Based on tuples from set theory.

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

oclint 0.9 / [stackoverflow]

mkdir build; cd build
scan-build cmake ..

....

oclint-json-compilation-database -v oclint_args \
  "-allow-duplicated-violations -enable-clang-static-analyzer \
  -enable-global-analysis -list-enabled-rules \

	# perform a fresh install of Ubuntu 17.10

	# upgrade the kernel to v4.13.10
	mkdir ~/kernel-v4.13.10
	cd ~/kernel-v4.13.10
	wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.10/linux-headers-4.13.10-041310_4.13.10-041310.201710270531_all.deb
	wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.10/linux-headers-4.13.10-041310-generic_4.13.10-041310.201710270531_amd64.deb
	wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.13.10/linux-image-4.13.10-041310-generic_4.13.10-041310.201710270531_amd64.deb
	sudo dpkg -i *.deb

	LD SP,$fffe ; $0000 Inizializza Stack- copia $fffe in SP (Stack Pointer)

	XOR A ; $0003 Setta a 0 la memoria da $8000-$9FFF (VRAM) (xor tra A e se stesso=tutti 0 essendo bit uguali)
	LD HL,$9fff ; $0004 Setta HL- puntatore per pulire la VRAM
	Addr_0007:
	LD (HL-),A ; $0007 Setta HL a 0 (essendo A tutti bit 0), decrementa HL portandolo a $9ffe
	BIT 7,H ; $0008 Bit piu significante di H=$9f= 10011111 ossia 1 - zero flag del registro F viene pulito
	JR NZ, Addr_0007 ; $000a jump if not zero to address 0x000C-0x0005=0x0007
	questa procedura qui sopra continua in loop scrivendo 0 in $9FFE,$9FFD...fintanto che
	il jump viene annullato=condizione 'not zero' vera.

	Windows.ApplicationModel.Activation.FileOpenPickerContinuationEventArgs
	Windows.ApplicationModel.Activation.FileSavePickerContinuationEventArgs
	Windows.ApplicationModel.Activation.FolderPickerContinuationEventArgs
	Windows.ApplicationModel.Activation.IContinuationActivatedEventArgs
	Windows.ApplicationModel.Activation.IFileOpenPickerContinuationEventArgs
	Windows.ApplicationModel.Activation.IFileSavePickerContinuationEventArgs
	Windows.ApplicationModel.Activation.IFolderPickerContinuationEventArgs
	Windows.ApplicationModel.Activation.IWebAccountProviderActivatedEventArgs
	Windows.ApplicationModel.Activation.IWebAccountProviderContinuationEventArgs
	Windows.ApplicationModel.Activation.WebAccountProviderActivatedEventArgs

	Latency Comparison Numbers
	--------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns
	Send 1K bytes over 1 Gbps network 10,000 ns 0.01 ms
	Read 4K randomly from SSD* 150,000 ns 0.15 ms