/***
 * 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.
 */
public class Solution {
    public int maxProfit(int[] prices) {
        int pmin = Integer.MAX_VALUE;
        int mprofit = 0;
        for (int i = 0; i < prices.length; i++) {
            if (pmin > prices[i])
                pmin = prices[i];
            mprofit = prices[i] - pmin > mprofit ? prices[i] - pmin : mprofit;
        }
        return mprofit;
    }
}

add BestTimetoBuyandSellStock.java