LeedCode --- Best Time to Buy and Sell Stock

题目链接

题意： find the maximum positive difference between the price on the ith day and the jth day

附上代码：

 class Solution {
 public:
     int maxProfit(vector<int> &prices) {
         if (prices.size() == )
              return ;
         // "minimum" holds the minimum price before the ith day.
         // "max_diff" holds the maximum difference between prices[i] and prices[j]
         // where 0 <= i < j < prices.size()
         int minimum = prices[], max_diff = ;
         for (unsigned int i = ; i < prices.size(); i++) {
             if (prices[i] - minimum > max_diff) {
                 max_diff = prices[i] - minimum;
             }
             if (prices[i] < minimum) {
                 minimum = prices[i];
             }
         }
         return max_diff;
     }
 };