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#121. Best Time to Buy and Sell Stock | LeetCode Python Solution

Problem​

LeetCode Problem

  1. Best Time to Buy and Sell Stock

Python Solution​

We use sliding window technique to detect best day to buy and keep track of maximum profit.

class Solution:
    def maxProfit(self, prices: List[int]) -> int:
        """
        Drawing to walk through the algorithm in different tests
        https://excalidraw.com/#json=RdBdGSRzQzSvdtAkNf4f-,hDL4m4lrm6Hzi73m_XCoxQ
        """

        # Initialize to buy at day 1 and sell at day 2
        buy, sell = 0, 1

        # Keep tracking of maximum profit so far
        maxProfitSoFar = 0

        while sell < len(prices):
            profit = prices[sell] - prices[buy]

            if profit < 0:
                # No profit, but we found a lower price point to buy
                buy = sell
            else:
                # Update maximum profit
                maxProfitSoFar = max(maxProfitSoFar, profit)

            # Increment sell day by 1
            sell += 1

        return maxProfitSoFar