 # Best Time to Buy and Sell Stocks I

Say you have an array, A, 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 (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

Return the maximum possible profit.

Input Format:

``````The first and the only argument is an array of integers, A.
``````

Output Format:

``````Return an integer, representing the maximum possible profit.
``````

Constraints:

``````1 <= len(A) <= 7e5
1 <= A[i] <= 1e7
``````

Examples:

``````Input 1:
A = [1, 2]

Output 1:
1

Explanation:
Buy the stock on day 0, and sell it on day 1.

Input 2:
A = [1, 4, 5, 2, 4]

Output 2:
4

Explanation:
Buy the stock on day 0, and sell it on day 2.
``````
NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a doubt? Checkout Sample Codes for more details. 