when to sell stock once after purchase code example

Example: buy and sell stock gfg

#include <iostream>
using namespace std;

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