In [53]:

    

const myStack = []
myStack.push(1)
myStack.pop()


    

    
Out[53]:





1

In [54]:

    

const myQ = []
myQ.push(1)
myQ.push(2)
myQ.shift()
myQ


    

    
Out[54]:





[ 2 ]

In [41]:

    

const createSLL = () => {
    let head = null
    
    const getHead = () => head
    
    const push = value => {
        let node = {value, next: null}
        if (!head) {
            head = node
        }
        else {
            let current = head
            while (current.next) {
                current = current.next
            }
            current.next = node
        }
    }
    return {getHead, push}
}


    

In [42]:

    

var sll = createSLL()


    

In [43]:

    

sll.push(3);
sll.push(4);
sll.push(5);


    

In [44]:

    

sll.getHead()


    

    
Out[44]:





{ value: 3, next: { value: 4, next: { value: 5, next: null } } }

In [45]:

    

var createDLL = () => {
    let head = null
    const getHead = () => head
    const push = value => {
        let current = head
        let previous = head
        if (!head) {
            head = {value, previous: null, next: null}
        }
        else {
            while (current && current.next) {
                previous = current
                current = current.next
            }
            current.next = {value, previous: current, next: null}
        }
    }
    return {getHead, push}
}


    

In [47]:

    

var dll = createDLL()
dll.push(2)
dll.push(3)
dll.push(4)
dll.push(5)


    

In [51]:

    

dll.getHead().next.previous


    

    
Out[51]:





{ value: 2,
  previous: null,
  next: 
   { value: 3,
     previous: [Circular],
     next: { value: 4, previous: [Circular], next: [Object] } } }

In [ ]:

    

var ListNode = val => {
    let value = val
    let next = null
    const getValue = () => val
    const setValue = newVal => {
        value = newVal
    }
    const getNext = () => next
    const setNext = nextNode => {
        next = nextNode
    }
    const appendEnd = endVal => {}
    return {getValue, setValue, getNext, setNext}
}


    

In [ ]:

    

var TreeNode = val => {
    let value = val
    let children = []
    const getValue = () => value
    const getChildren = () => children
    const setValue = newVal => {value = newVal}
    const addChild = childNode => {children.push(childNode)}
    return{getValue, getChildren, setValue, addChild}
}


    

In [1]:

    

var TreeNode = val => {
    let value = val
    let left = null
    let right = null
    const getValue = () => value
    const setValue = newVal => {value = newVal}
    const getLeft = () => left
    const getRight = () => right
    const setLeft = Node => {left = Node}
    const setRight = Node => {right = Node}
    return{getValue, setValue, getLeft, getRight, setLeft, setRight}
}


    

In [5]:

    

var IOT = node => {
    if (node) {
        IOT(node.getLeft())
        console.log(node.getValue())
        IOT(node.getRight())
    }
}


    

In [6]:

    

var PreOT = node => {
    if (node) {
        console.log(node.getValue())
        PreOT(node.getLeft())
        PreOT(node.getRight())
    }
}


    

In [7]:

    

var PostOT = node => {
    if (node) {
        PostOT(node.getLeft())
        PostOT(node.getRight())
        console.log(node.getValue())
    }
}


    

In [11]:

    

var myNode = TreeNode(10)
myNode.setLeft(TreeNode(5))
myNode.getLeft().setLeft(TreeNode(3))
myNode.getLeft().setRight(TreeNode(7))
myNode.setRight(TreeNode(20))


    

In [12]:

    

IOT(myNode)


    

    




3
5
7
10
20

In [13]:

    

PreOT(myNode)


    

    




10
5
3
7
20

In [14]:

    

PostOT(myNode)


    

    




3
7
5
20
10

In [7]:

    

var twoSum = (nums, target) => {
    for (const i of [...Array(nums.length).keys()]) {
        if (nums.includes(target - nums[i])) {
            const j = +Object.keys(nums).find(key => nums[key] == target - nums[i] && key != i)
            if (j) {
                return [i, j]
            }
        }
    }
    return "not found"
}


    

In [20]:

    

function ListNode(val) {
    this.val = val;
    this.next = null;
}


    

In [21]:

    

function appendAtEnd(Node, val) {
    if (!Node.next) {
        Node.next = ListNode(value)
    }
    else {
        appendAtEnd(Node.next, val)
    }
}


    

In [24]:

    

var list1 = ListNode(2)


    

In [26]:

    

list1


    

In [ ]:

    




    

In [ ]:

    




    

In [ ]:

    




    

In [ ]:

    




    

In [86]:

    

function foo() {
    let a = 2
    function bar() {
        console.log(a)
    }
    return bar
}


    

In [87]:

    

var baz = foo()


    

In [88]:

    

baz()


    

    




2

In [ ]:

    




    

In [93]:

    

var foo = () => {
    let  a = 2
    var bar = () => console.log(a)
    return {bar}
}


    

In [94]:

    

var baz = foo()


    

In [96]:

    

baz.bar()


    

    




2

In [ ]: