Buy Sell Stocks

// Greedy Approach: Iterate through the prices and maintain buy price and maxprofit gained up until that point. -> O(N), O(1)
int maxProfit(int[] prices, int n) {
    int buy = prices[0], max_profit = 0;
    for (int i=1; i<n; i++) {
        if (buy > prices[i]) {
            buy = prices[i];
        } else if (prices[i] - buy > max_profit) {
            max_profit = prices[i] - buy;
        }
    }
    return max_profit;
}