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Best Time to Buy and Sell Stock

Problem Statement

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.

Leetcode Link

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 <= 3 * 105
  • 0 <= prices[i] <= 3 * 104

Code

Python Code

class Solution:
def maxProfit(self,prices):
left = 0
right = 1
max_profit = 0
while right < len(prices):
currentProfit = prices[right] - prices[left]
if prices[left] < prices[right]:
max_profit =max(currentProfit,max_profit)
else:
left = right
right += 1
return max_profit