Stock Picker – Interview Coderbyte – Code challenge – JavaScript Solution Source Code Answers

Stock Picker – Coderbyte

Have the function StockPicker(arr) take the array of numbers stored in arr which will contain integers that represent the amount in dollars that a single stock is worth, and return the maximum profit that could have been made by buying stock on day x and selling stock on day y where y > x. For example: if arr is [44, 30, 24, 32, 35, 30, 40, 38, 15] then your program should return 16 because at index 2 the stock was worth $24 and at index 6 the stock was then worth $40, so if you bought the stock at 24 and sold it at 40, you would have made a profit of $16, which is the maximum profit that could have been made with this list of stock prices.

If there is not profit that could have been made with the stock prices, then your program should return -1. For example: arr is [10, 9, 8, 2] then your program should return -1.

function StockPicker(arr) { 
    var profit=-1; // Initialize the maximum profit to -1
    var buyPrice=arr[0]; // Initialize the buying price to the first element of the array
    for(var i=1; i<arr.length; i++){ // Loop through the array starting from the second element
        if(arr[i]<buyPrice){ // If the current element is smaller than the buying price
            buyPrice=arr[i]; // Update the buying price
        }
        else if( (arr[i]-buyPrice) > profit){ // If selling the stock at the current price will give a greater profit than the previous maximum profit
            profit=arr[i]-buyPrice; // Update the maximum profit
        }
    }
    
  return profit; // Return the maximum profit 
}
   
// keep this function call here 
console.log(StockPicker(readline()));