Best Time to Buy and Sell Stock

class Solution {
public:
    int maxProfit(vector<int> &prices) {
        int len=prices.size();
        if(len<=1) return 0;
        
        int low[len];
        low[0]=prices[0];
        for(int i=1;i<len;i++)
        {
            if(prices[i]<low[i-1])
                low[i]=prices[i];
            else
                low[i]=low[i-1];
        }
        
        int max=0;
        for(int i=1;i<len;i++)
        if(prices[i]-low[i-1]>max)
            max=prices[i]-low[i-1];
        
        return max;
    }
};