Untitled

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        
        N = len(prices)
        stack = []
        globalMax = 0
        
        for i in range(N):
            while stack and stack[-1] > prices[i]:
                stack.pop()

            if stack:
                globalMax = max(globalMax, prices[i] - stack[0])
                
            stack.append(prices[i])
        
        
        return globalMax