Leetcode#121 Best Time to Buy and Sell Stock

 1 int maxProfit(vector<int> &prices) {
 2         int profit = 0;
 3         int climax = -1;
 4         
 5         for (int i = prices.size() - 1; i >= 0; i--) {
 6             if (prices[i] >= climax)
 7                 climax = prices[i];
 8             else
 9                 profit = max(profit, climax - prices[i]);
10         }
11         
12         return profit;
13 }