题目链接

买卖股票的最佳时机II

题目描述

image.png

实现代码

思路：将数组的下标看成x，每个值看成y，那么在直角坐标系中这就是一个折线，要想找到赚取的最大利润，其实就是每个上升阶段的总和，实现代码如下：

  1. class Solution:
  3.     def maxProfit(self, prices: List[int]) -> int:
  5.         n = len(prices)
  6.         if n == 1:
  7.             return 0
  8.         cur_buy = prices[0]
  9.         cur_sale = -1
  10.         ans = 0
  12.         first = True
  14.         allCalculate = True
  16.         for price in prices:
  18.             if first:
  19.                 first = False
  20.                 continue
  22.             if price < cur_buy:
  23.                 if cur_sale == -1:
  24.                     cur_buy = price
  25.                     continue
  26.                 ans += cur_sale - cur_buy
  27.                 cur_buy = price
  28.                 cur_sale = -1
  29.                 allCalculate = True
  30.                 continue
  32.             if price > cur_sale:
  33.                 cur_sale = price
  34.                 allCalculate = False
  35.                 continue
  37.             if price < cur_sale:
  38.                 ans += cur_sale - cur_buy
  39.                 allCalculate = True
  40.                 cur_buy = price
  41.                 cur_sale = -1
  43.         return ans if allCalculate else ans + cur_sale - cur_buy