Java for LeetCode 121 Best Time to Buy and Sell Stock

Say you have an array for which the i^th 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.

解题思路：

一次遍历，每次找到最小的Buy点即可，JAVA实现如下：

    public int maxProfit(int[] prices) {
        int buy = 0;
        int profit = 0;
        for (int i = 0; i < prices.length; ++i) {
            if (prices[buy] > prices[i])
                buy = i;
            profit = Math.max(profit, prices[i] - prices[buy]);
        }
        return profit;
    }