EJSohn

enum ArithmeticExpression {
    case number(Int)
    indirect case addition(ArithmeticExpression, ArithmeticExpression)
    indirect case multiplication(ArithmeticExpression, ArithmeticExpression)
}

EJSohn

func evaluate(_ expression: ArithmeticExpression) -> Int {
    switch expression {
        case let .number(value):
            return value
        case let .addition(left, right):
            return evaluate(left) + evaluate(right)
        case let .multiplication(left, right):
            return evaluate(left) * evaluate(right)
    }
}

EJSohn

public enum Result<Value> {
    case Success(Value)
    case Failure(NSData?, ErrorType)
}

EJSohn

# install ubuntu packages
apt-get install -y make build-essential libssl-dev zlib1g-dev libbz2-dev \
libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev libncursesw5-dev \
xz-utils tk-dev

touch ~/.bash_profile

# install pyenv
git clone https://github.com/pyenv/pyenv.git ~/.pyenv
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bash_profile

EJSohn

echo "Need root permission."
sudo echo "Done."
read -p "1. Enter username: " username
read -p "2. Enter comment: " comment
sudo adduser $username -c "$comment" --firstuid 10000 --ingroup developers --disabled-password --gecos ""
echo "User created!"
echo -e "$username\n$username" | sudo passwd $username >/dev/null 2>&1
sudo passwd -e $username >/dev/null 2>&1
echo "username : $username"
echo "initial password : $username"

EJSohn

package main
import "fmt"

func main() {
  fmt.Println("hello world")
}

EJSohn

package main
import "fmt"

func main() {
  fmt.Println("hello world")
}

EJSohn

func twoSum(nums []int, target int) []int {
    // map from int -> int
    m := make(map[int]int)
    
    // python like enumerate
    for i, num := range(nums) {
        // get value and check existence in map
        // and in if statement where ok is the boolean comparison value
        if index, ok := m[target - num]; ok { 
            // construct array and return values 

EJSohn

// c like struct
type TreeNode struct {
    Value int
    Left, Right *TreeNode // pointers
}


func DfsInOrder(treeNode *TreeNode) {
    if treeNode == nil {
        return

EJSohn

struct LinkNode {
  Value int
  Prev, Next *LinkNode
}