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description:

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:

1 <= prices.length <= 105

0 <= prices[i] <= 104

Solution:

public class Solution {
    public int maxProfit(int[] prices) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if(prices == null || prices.length == 0) return 0;
        int min = prices[0];
        int max = Integer.MIN_VALUE;

        for(int i = 0; i < prices.length; i++){
            int money = prices[i] - min;
            if(money > max) max = money;
            if(prices[i] < min) min = prices[i];
        }

        return max;


    }
}

leetcode

challenge

Here is the link for the problem:
https://leetcode.com/problems/best-time-to-buy-and-sell-stock/