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.

 

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.

Solution

class Solution {

public int maxProfit(int[] prices) {

int maxProfit=0;

int buyPrice=prices[0];

for(int i=1; i<prices.length; i++){

if(prices[i]<buyPrice){

buyPrice=prices[i];

}

maxProfit=Math.max(maxProfit, prices[i]-buyPrice);

}

return maxProfit;

}

}