[leetcode]Best Time to Buy and Sell Stock @ Python

原題地址：https://oj.leetcode.com/problems/best-time-to-buy-and-sell-stock/

題意：

Say you have an array for which the ith element is the price of a given stock on day i.

If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), design an algorithm to find the maximum profit.

解題思路：掃描一遍數組，使用low來標記最低價位，如果有更低的價位，置換掉。

代碼：

class Solution:
    # @param prices, a list of integer
    # @return an integer
    def maxProfit(self, prices):
        if len(prices) <= 1: return 0
        low = prices[0]
        maxprofit = 0
        for i in range(len(prices)):
            if prices[i] < low: low = prices[i]
            maxprofit = max(maxprofit, prices[i] - low)
        return maxprofit