0121 - Best Time to Buy and Sell Stock

0121 - Best Time to Buy and Sell Stock

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

Examples

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.

Input: prices = [7,6,4,3,1] Output: 0 Explanation: In this case, no transactions are done and the max profit = 0.

Constraints

1 <= prices.length <= 105 0 <= prices[i] <= 104

Java Solution

class Solution {
    public int maxProfit(int[] prices) {
        int maxProfit = 0;
        int minPrice = Integer.MAX_VALUE;
        for(int i = 0; i < prices.length; i++) {
            if(prices[i] < minPrice) {
                minPrice = prices[i];
            } else if (prices[i] - minPrice > maxProfit) {
                maxProfit = prices[i] - minPrice;
            }
        }
        return maxProfit;
    }
}