Discussion on: Daily Challenge #228 - Best Profit in Single Sale

#include <iostream>
#include <vector>
using namespace std;

// returns the maximum profit (or minimum loss) user can make
// by buying and selling one item 
int max_profit(vector<int> prices){
    // stores the maximum profit made so far
    int maxProfitSoFar = prices[1] - prices[0];

    // stores the minimum price seen so far
    int minPriceSoFar = min(prices[0], prices[1]);

    for(int i = 2; i < prices.size(); i++){
        // maximum profit will be the maximum of
        // (current price - minimum price seen before) and maximum profit so far
        maxProfitSoFar = max(prices[i] - minPriceSoFar, maxProfitSoFar);

        // minimum price will be minimum of
        // current price and minimum price seen before
        minPriceSoFar = min(prices[i], minPriceSoFar);
    }

    return maxProfitSoFar;
}

// main function
int main(){
    cout << max_profit({3, 10, 8, 4}) << "\n"; // output -> 7
    cout << max_profit({10, 7, 5, 8, 11, 9}) << "\n"; // output -> 6
    cout << max_profit({3, 4}) << "\n"; // output -> 1
    cout << max_profit({9, 9}) << "\n"; // output -> 0
    cout << max_profit({10, 7, 5, 4, 1}) << "\n"; // output -> -1
    return 0;
}