【LeetCode】Best Time to Buy and Sell Stock II

https://oj.leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/

每笔赚钱交易都做：

class Solution {
public:
    int maxProfit(vector<int> &prices) {
        if (prices.size() < 2) {
            return 0;
        }
        
        vector<int> diff;
        for (vector<int>::size_type i = 1; i < prices.size(); ++i) {
            diff.push_back(prices[i] - prices[i-1]);
        }
        
        int profile = 0;
        for (vector<int>::size_type i = 0; i < diff.size(); ++i) {
            if (diff[i] >= 0) { profile += diff[i]; }
        }
        
        return profile;
    }
};