Best Time to Buy and Sell Stock

问题描述
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: 5
​
max. 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: 0
​
In this case, no transaction is done, i.e. max profit = 0.
题目链接
​https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/​
Python
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 sys
        lowprice = sys.maxint
        profit = 0
        for price in prices:
            if price < lowprice:
                lowprice = price
            if price - lowprice > profit:
                profit = price -lowprice
        return profit
Java
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;
    }
}
Golang
DP 求解
package main
​
import (
    "fmt"
)
​
func MaxProfit(prices []int) int {
    low := prices[0]
    result := 0
    for 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[:]))
}
Move Zeroes
Best Time to Buy and Sell Stock II
Last updated 2 years ago