Best Time to Buy and Sell Stock II

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

        int max=0;
        int start=prices[0];
        int last=prices[0];
        int sz = prices.size();
        for(int i=1; i<sz; ++i)
        {
            if(prices[i]>=prices[i-1])
            {
                last=prices[i];
                if(i==sz-1)
                    max += (last-start);
            }
            else
            {
                max += (last-start);
                start=prices[i];
                last=prices[i];
            }
         }
        return max;
    }
};