Leetcode#122 Best Time to Buy and Sell Stock II

int maxProfit(vector<int> &prices) {
if (prices.empty())
return 0;

int profit = 0;
int climax = prices[prices.size() - 1];

for (int i = prices.size() - 2; i >= 0; i--) {
if (prices[i] >= prices[i + 1]) {
profit += climax - prices[i + 1];
climax = prices[i];
}
}
profit += climax - prices[0];

return profit;
}