Best Time to Buy and Sell Stock

Given an array prices, where prices[i] is the price of a stock on day i, you may complete at most one transaction: buy on one day and sell on a later day. Return the maximum profit. Return 0 if no profitable transaction exists. Input Format First line: integer n Second line: n daily prices Output Format Print the maximum profit. Constraints 1 <= n <= 2 * 10^5 0 <= prices[i] <= 10^9 Example Input 6 7 1 5 3 6 4 Output 5