Coding interview questions set 7

Let's begin with set 7,

Q15) Best Time to Buy and Sell Stock

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



var maxProfit = function(prices) {

    var min = Number.MAX_SAFE_INTEGER; 

    var max = 0;

    for (var i = 0; i < prices.length; i++) {

        min = Math.min(min, prices[i]);

        max = Math.max(max, prices[i] - min);


    return max;



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