Best_Time_to_Buy_and_Sell_Stock.js

// You are given an array prices where prices[i] is the price of a given stock on the ith day.

// You want to maximize your profit by choosing a single day to buy one stock and choosing a different day in the future to sell that stock.

// Return the maximum profit you can achieve from this transaction. If you cannot achieve any profit, return 0.

// Example 1:

// Input: prices = [7,1,5,3,6,4]
// Output: 5
// Explanation: Buy on day 2 (price = 1) and sell on day 5 (price = 6), profit = 6-1 = 5.
// Note that buying on day 2 and selling on day 1 is not allowed because you must buy before you sell.

// Example 2:

// Input: prices = [7,6,4,3,1]
// Output: 0
// Explanation: In this case, no transactions are done and the max profit = 0.

// Constraints:

//     1 <= prices.length <= 105
//     0 <= prices[i] <= 104

/**
 * @param {number[]} prices
 * @return {number}
 */
var maxProfit = function (prices) {
  let maxel = 0,
    minel = prices[0];
  for (let i = 0; i < prices.length; i++) {
    minel = Math.min(minel, prices[i]);
    maxel = Math.max(maxel, prices[i] - minel);
  }
  return maxel;
};