Skip to content

121. Best Time To Buy And Sell Stock

Array Dynamic Programming

Problem - 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:

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

Solutions

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        min_price = float('inf')
        best = 0

        for day_price in prices:
            min_price = min(min_price, day_price)
            best = max(best, day_price - min_price)

        return best

Submission Stats:

  • Runtime: 132 ms (22.65%)
  • Memory: 26.9 MB (32.63%)