apple-stocks.js

/**
 *  I have an array stock_prices_yesterday where:
 *
 *    - The indices are the time in minutes past trade opening time, which was 9:30am local time
 *    - The values are the prices in dollars of Apple stock at the time
 *
 *  For example, the stock cost $500 at 10:30am, so stock_prices_yesterday[60] = 500;
 *
 *  Write an efficient algorithm for computing the best profit I could have made from 1 purchase
 *  and 1 sale of 1 Apple stock yesterday
 *
 */
var apple = [1000, 200, 800, 1100, 400, 1400];
var min = apple.shift();
function bestProfit(stock_prices_yesterday) {
  var minValue = stock_prices_yesterday.shift();
  var maxProfit = 0;
  for(var i = 0; i < stock_prices_yesterday.length; i++) {
    if(stock_prices_yesterday[i] < minValue) {
      minValue = stock_prices_yesterday[i];
    }
    if ( stock_prices_yesterday[i] > minValue ) {
      if(stock_prices_yesterday[i] - minValue > maxProfit) {
        maxProfit = stock_prices_yesterday[i] - minValue;
      }
    }
  }
  return maxProfit;
}
console.log(bestProfit(apple));