LeetCode-in-All

121. Best Time to Buy and Sell Stock

Easy

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.

Example 1:

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.

Example 2:

Input: prices = [7,6,4,3,1]

Output: 0

Explanation: In this case, no transactions are done and the max profit = 0.

Constraints:

Solution

public class Solution {
    public int MaxProfit(int[] prices) {
        int min = int.MaxValue;
        int profit = 0;
        int max = 0;
        for (int i = 0; i < prices.Length; i++) {
            if (prices[i] < min) {
                min = prices[i];
            }
            profit = prices[i] - min;
            max = Math.Max(profit, max);

        }
        return max;
    }
}