121_best_time_to_buy_and_sell_stock.py

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        l,r = 0,1
        maxP = 0
        while r<len(prices):
            if(prices[l]<prices[r]):
                profit = prices[r]-prices[l]
                maxP = max(profit,maxP)
            else:
                l = r
            r+=1
        return maxP