Best Time to Buy and Sell Stock

Best Time to Buy and Sell Stock (Single Transaction) You are given an integer array prices of length n, where prices[i] is the stock price on day i. You may complete at most one transaction: choose one day to buy and a later day to sell (you must buy before you sell). Return the maximum profit you can achieve; if no profit is possible, return 0. Input Format Line 1: an integer n, the length of the array Line 2: n integers representing prices Output Format Print one integer: the maximum profit Constraints 1 <= n <= 2 * 10^5 0 <= prices[i] <= 10^9 Examples (stdin -> stdout) Example Input 6 7 1 5 3 6 4 Output 5