Leetcode best time to Buy and Sell Stock

Say you has an array for which the i-th element is the price of a given-stock on day I.

If you were-permitted-to-complete at most one transaction (ie, buy one and sell one share of the stock), design an AL Gorithm to find the maximum profit.

Problem Solving Ideas:

The reason why I did wrong is that I thought that if we found the minimum and maximum value, we would get the maximum profit. But the stock trading is in order, first buy after sell. So the minimum value must be left, and then compare the difference between the value on the right and the minimum, the biggest is the maximum profit.

Scan from left to right. And keep track the minimal price in left. So, each step, only calculate the difference between and minimal.
If this diff large than the current Max difference, replace it.

Java Code

 Public int maxprofit (int[] prices) {       int Profit = 0;        int min = integer.max_value;         for (int i = 0; i < prices.length; i++) {           = math.min (min, prices[i]);            = Math.max (Profit, Prices[i]- min);       }        return profit;    }

Reference:

1. http://fisherlei.blogspot.com/2013/01/leetcode-best-time-to-buy-and-sell.html

2. http://www.programcreek.com/2014/02/leetcode-best-time-to-buy-and-sell-stock-java/

Leetcode best time to Buy and Sell Stock