暴力+DP：买卖股票的最佳时机

 1 int maxProfit(int* prices, int pricesSize)
 2 {
 3     if (pricesSize == 0 || pricesSize == 1)
 4         return 0;
 5     int i, j;
 6     int sum = 0;
 7 
 8     for (i = 0; i < pricesSize-1; i++)
 9     {
10         for (j = i + 1; j < pricesSize; j++)
11         {
12             sum = (sum > (prices[j] - prices[i]) ? sum : (prices[j] - prices[i]));
13         }
14     }
15     
16     return sum;
17 }

 1 int maxProfit(int* prices, int pricesSize)
 2 {
 3     if (pricesSize < 2)
 4         return 0;
 5     
 6     int sum = 0;
 7     int minVal = prices[0];
 8 
 9     for (int i = 1; i < pricesSize; i++)
10     {
11         sum = (sum > (prices[i] - minVal) ? sum : (prices[i] - minVal));
12         minVal = (minVal < prices[i] ? minVal : prices[i]);
13     }
14 
15     return sum;
16 }