##Interview Questions and Prep

Javascript Questions

1. Stock Prices

Write a method that takes an array of historical stock prices for a single stock (prices on days 0, 1, 2...), and outputs the most profitable pair of days (indices) on which you should have first bought and then sold the stock.

For example: prices = [ 44, 30, 24, 32, 35, 30, 40, 38, 15 ]

e.g., $44, $30, $24…

stock_picker( prices ) => [ 2, 6 ]

buy at $24, sell at $40 == $16 profit

**** Code below here ****

HackReactor Prep

Solutions to practice problems written in Javascript.

Find the sole odd or even number.

/* Given a string of even and odd numbers, find which is the sole even number or the sole odd number.

The return value should be 1-indexed, not 0-indexed.

Examples : detectOutlierValue("2 4 7 8 10"); // => 3 - Third number is odd, while the rest of the numbers are even detectOutlierValue("1 10 1 1"); //=> 2 - Second number is even, while the rest of the numbers are odd */

// input: string of numbers, only 1 sole even or odd number // output: an index of the sole even or odd number // process: change string to array, check if odd or even, find where there is a sole odd or even

// need a way to identify which is the unique number // frequency hash of with keys being odd // return index of valuesArray of length

function detectOutlierValue(str) { var arrayFromStringInput = str.split(" "); var resultsArray = arrayFromStringInput.filter(function(elem, index){

if (elem % 2 === 0){
  console.log(index + elem);
  return index
}

}); return resultsArray; }

detectOutlierValue("4 12 6 8");

Udacity Technical Interviews Course

Solutions to practice problems written in Javascript.

##Binary Trees

####Types of Traversal

        B
       / \
      /   \
     /     \
    A       C

######All types of Traversal -Start at bottomest left -Traverse left to right

Preorder B, A, C root, leaf, leaf

Inorder A, B, C leaf, root, leaf

Postorder A, C, B leaf, leaf, root

####Implement a Binary Tree

The following is given. (Converted it from Java to Javascript).

// function Node(value,left=null,right=null){
  // function Node(value,left,right){
    function Node(value){
     this.value = value;
  // this.left = left;
  // this.right = right;
}

function BinaryTree(root){
  this.root = Node(root);
}

// Node.prototype.preorderSearch = function(start, find_val){
//   if(this.value === null){return false}
//   if(this.value === find_val){
//     return true;
//   } else {
//     this.preorderSearch(this.left);
//     this.preorderSearch(this.right);
//     return false;
//   }
// }



//To set up a node 
var n = new Node(1);


// # Set up tree
//tree = BinaryTree(1)
// tree.root.left = Node(2)
// tree.root.right = Node(3)
// tree.root.left.left = Node(4)
// tree.root.left.right = Node(5)

// // # Test search
// // # Should be True
// console.log(tree.search(4));
// // # Should be False
// console.log(tree.search(6));

// // # Test print_tree
// // # Should be 1-2-4-5-3
// console.log(tree.print_tree());