The interview was scheduled two to three weeks after talking to the recruiter. It was a video call interview lasting about 40 minutes. I explained my approach and then coded. The interviewer was nice and helpful, giving me one to two hints during the approach explanation. After I completed the code, they asked for other ways of doing it, and I provided one to two alternative methods. They kept my application on hold for about a month. The recruiter said my application was in consideration; they didn't reject me but also didn't respond regarding the next round for another whole month. So, I joined somewhere else.

Say you have an array for which the ith element is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (i.e., buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Note that you cannot sell a stock before you buy one.

Ex: Input: [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. Not 7-1 = 6, as selling price needs to be larger than buying price.