StockandSell.java

import java.util.ArrayList;
 
// Solution structure
class Interval {
    int buy, sell;
}
 
class StockBuySell {
    // This function finds the buy sell schedule for maximum profit
    void stockBuySell(int price[], int n)
    {
        // Prices must be given for at least two days
        if (n == 1)
            return;
 
        int count = 0;
 
        // solution array
        ArrayList<Interval> sol = new ArrayList<Interval>();
 
        // Traverse through given price array
        int i = 0;
        while (i < n - 1) {
            
            while ((i < n - 1) && (price[i + 1] <= price[i]))
                i++;
 
           
            if (i == n - 1)
                break;
 
            Interval e = new Interval();
            e.buy = i++;
            // Store the index of minima
 
            // Find Local Maxima.  Note that the limit is (n-1) as we are
            // comparing to previous element
            while ((i < n) && (price[i] >= price[i - 1]))
                i++;
 
            // Store the index of maxima
            e.sell = i - 1;
            sol.add(e);
 
            // Increment number of buy/sell
            count++;
        }
 
        // print solution
        if (count == 0)
            System.out.println("There is no day when buying the stock "
                               + "will make profit");
        else
            for (int j = 0; j < count; j++)
                System.out.println("Buy on day: " + sol.get(j).buy
                                   + "        "
                                   + "Sell on day : " + sol.get(j).sell);
 
        return;
    }
 
    public static void main(String args[])
    {
        StockBuySell stock = new StockBuySell();
 
        // stock prices on consecutive days
        int price[] = { 100, 180, 260, 310, 40, 535, 695 };
        int n = price.length;
 
        // function call
        stock.stockBuySell(price, n);
    }
}