121. Best Time to Buy and Sell Stock

基本题意

题解

动态规划方法

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        pre_min = prices[0]
        ans = 0
        for price in prices:
            ans = max(ans, price-pre_min)
            pre_min = min(pre_min, price)
        return ans