LeetCode OJ

题目：

Say you have an array for which the i^th element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

解题思路：

遇到price[i] < price[i-1] ,则将前一段时间的收益加上。注意处理末尾元素。

代码：

class Solution {
public:
    int maxProfit(vector<int> &prices) {
        if (prices.size() == 0) {
            return 0;
        }
        int lower = 0, higher = 0;
        int ans = 0;

        for (int i = 1; i < prices.size(); i++){
            if (prices[i] >= prices[higher]){
                higher++;
            }
            else {
                ans += (prices[higher] - prices[lower]);
                lower = i;
                higher = i;
            }
        }
        if (prices[prices.size()-1] > prices[lower]) {
            ans += (prices[prices.size() - 1] - prices[lower]);
        }
        return ans;

    }
};