【LeetCode】Best Time to Buy and Sell Stock（买卖股票的最佳时间）

【LeetCode】Best Time to Buy and Sell Stock（买卖股票的最佳时间）
题目链接：https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/
难度：Easy
题目描述：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.题目大意：给一个价格数组prices[]，prices[i]代表股票在第i天的售价，只能做一次交易（买一次卖一次），求最大收益。
思路：遍历一遍数组，用一个变量记录遍历过的最小值，在用另一个变量记录当前值和最小值的差的最大值，不断更新，最后即为最大利润。class Solution {
public int maxProfit(int prices[]) {
int minprice = Integer.MAX_VALUE;
int maxprofit = 0;
for (int i = 0; i < prices.length; i++) {
if (prices[i] < minprice)//寻找更小的买入价
minprice = prices[i];//不断更新的最小值
else if (prices[i] - minprice > maxprofit)
maxprofit = prices[i] - minprice;//存放每次利润的更大的值
}
return maxprofit;
}
}

日期：2018/2/27-22:27