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.

**Example 1:**

Input: [7, 1, 5, 3, 6, 4]Output: 5max. difference = 6-1 = 5 (not 7-1 = 6, as selling price needs to be larger than buying price)

**Example 2:**

Input: [7, 6, 4, 3, 1]Output: 0In this case, no transaction is done, i.e. max profit = 0.

https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/

DP的入门题目,先用模拟做

class Solution(object):def maxProfit(self, prices):""":type prices: List[int]:rtype: int"""import syslowprice = sys.maxintprofit = 0for price in prices:if price < lowprice:lowprice = priceif price - lowprice > profit:profit = price -lowpricereturn profit

暴力求解

class Solution {public int maxProfit(int[] prices) {int max = 0;int curMin = Integer.MAX_VALUE;for (int i = 0; i < prices.length; i++) {curMin = Math.min(curMin, prices[i]);max = Math.max(max, prices[i] - curMin);}return max;}}

DP 求解

package mainimport ("fmt")func MaxProfit(prices []int) int {low := prices[0]result := 0for i := 1; i < len(prices); i++ {if prices[i] < low {low = prices[i]}if prices[i]-low > result {result = prices[i] - low}}return result}func main() {a := []int{7, 3, 1, 2, 6, 8}fmt.Println(MaxProfit(a[:]))}