LFCodeChallenge

var stockPrices = [10, 7, 5, 8, 11, 9];

/*
Takes an array of stock prices and returns the best profit could have been made from 1 purchase and 1 sale of 1 stock
*/
function getProfit(inputArray){
  //find minimum of first 2 items of the array
  var min = inputArray[0] < inputArray[1] ? inputArray[0] : inputArray[1];
  //find difference of second item minus first
  var diff = inputArray[1] - inputArray[0];
  //optional container for buy, sell and profit margin
  var trade = {buy: 0, sell: 0, profit: diff};
  //iterate over each item of array, forEach is faster and safer than for loop
  inputArray.forEach(function(price, index){
    //skip first 2 since we have already compared them
    if(index>1){
      //if current price is less than minimum then current price is the new minimum
      if (price < min) min = price;
      //if current price minus minimum is bigger than previous difference then new difference is equal current price minus current minimum
      if (price - min > diff) diff = price - min;
      //optional, if profit/diff has increased, store the current price as well as the best minimum
      if (trade.profit < diff) {
        trade.buy = min;
        trade.sell = price;
        trade.profit = diff;
      }
    }
  });
  //optional, print buy, sell and profit margins
  console.log('Buy when $'+trade.buy+' and sell when $'+trade.sell+' for profit of $'+trade.profit);
  //return the best profit
  return (diff);
}

//print output
console.log(getProfit(stockPrices));