Reza Irianto rezaramadhanirianto

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

	long sum = 0, max = Integer.MIN_VALUE, min = Integer.MAX_VALUE;
	for(int num: nums) sum += num;

	for(int num: nums){
	max = Math.max(max, sum - num);
	min = Math.min(min, sum - num);
	}
	// return max & min
	return new int[]{max, min};

	Below are the Big O performance of common functions of different Java Collections.


	List \| Add \| Remove \| Get \| Contains \| Next \| Data Structure
	---------------------\|------\|--------\|------\|----------\|------\|---------------
	ArrayList \| O(1) \| O(n) \| O(1) \| O(n) \| O(1) \| Array
	LinkedList \| O(1) \| O(1) \| O(n) \| O(n) \| O(1) \| Linked List
	CopyOnWriteArrayList \| O(n) \| O(n) \| O(1) \| O(n) \| O(1) \| Array

	Big O complexities for common methods of Java Collections and common sorting algorithms.


	Complexity (Best to Worst)
	===================================================================================================
	O(1) < O(log n) < O(n) < O(n log n) < O(n^2) < O(2^n) < O(n!)


	Collections
	===================================================================================================

	syntax="proto3";

	package output;

	option go_package = "/output";
	import "google/protobuf/empty.proto";

	message OutputRequest{
	string title = 1;
	}

	package main

	import (
	"context"
	"fmt"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"grpc/my-simple-grpc/output"
	"time"
	)