# 122. Best Time to Buy and Sell Stock II

`Input: prices = [7,1,5,3,6,4]Output: 7Explanation: Buy on day 2 (price = 1) and sell on day 3 (price = 5), profit = 5-1 = 4.Then buy on day 4 (price = 3) and sell on day 5 (price = 6), profit = 6-3 = 3.`
`Input: prices = [1,2,3,4,5]Output: 4Explanation: Buy on day 1 (price = 1) and sell on day 5 (price = 5), profit = 5-1 = 4.Note that you cannot buy on day 1, buy on day 2 and sell them later, as you are engaging multiple transactions at the same time. You must sell before buying again.`
`Input: prices = [7,6,4,3,1]Output: 0Explanation: In this case, no transaction is done, i.e., max profit = 0.`
`class Solution {public:    int maxProfit(vector<int>& prices) {        int len = prices.size();        int min_p = 0;        int max_p = 0;        int ans = 0;        for(int i=0; i<len; i++){            while(i+1<len && prices[i+1] < prices[i]){                i++;            }            min_p = prices[i];            while(i+1<len && prices[i+1] > prices[i]){                i++;            }            max_p = prices[i];            ans += max_p - min_p;        }        return ans;            }};`

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