Coding challenge #10

StockN.java

import java.io.*;
import java.util.*;

public class StockN
{
    // Input format:
    // n
    // numbers (daily prices)
    private static void stockBuySell(int price[], int n)
    {
      int count = 0;
        
        int buy[] = new int[(n/2) + 1];
        int sell[] = new int[(n/2) + 1];
        
        int i = 0;
        
        while (i < n-1)
        {
          // Find local Minima. Note that the limit is (n-2) as we are
          // comparing present element to the next element.
          while ((i < n - 1) && (price[i+1] <= price[i]))
            i++;
          
          // If we reached the end, break as no further solution possible
          if (i == n-1)
            break;
          
          // Store the index of minima
          buy[count] = i++;
          
          // Now, find Local Maxima. Note the 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
          sell[count] = i-1;
          
          // Increment count of buy/sell pairs
          count++;
        }
        
        if (count == 0)
        {
          System.out.println("There is no day when buying the stock will make profit\n");
        }
        else
        {
          for (int j = 0; j < count; j++)
            System.out.printf("Buy on day: %d\t Sell on day: %d\n", buy[j], sell[j]);
        }
    }
    
    public static void main (String [] args)
    {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int price[] = new int[n];
        int idx = 0;
        while ( in.hasNextInt() )
        {
            price[idx++] = in.nextInt();
        }

        if (n <= 1)
          return;
        
        stockBuySell(price, n);
        
        return;
    }
}

StockN3.java

import java.io.*;
import java.util.*;
// http://www.geeksforgeeks.org/stock-buy-sell/
public class Stock
{
    // Input format:
    // n
    // numbers (daily prices)

    public static void main (String [] args)
    {   
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int price[] = new int[n];
        int idx = 0;
        while ( in.hasNextInt() )
        {   
            price[idx++] = in.nextInt();
        }   

        int A[][] = new int[n][n];

        for (int i = 0; i < n - 1; i++)
        {   
            int j = i + 1;
            if (price[j] > price[i]) 
            {   
                A[i][j] = price[j] - price[i];
            }   
        }   

        for (int d = 0; d < n; d++)
        {   
            for (int j = 0; j < n - d; j++)
            {   
                int max = 0;
                for (int k = 0; k < d; k++)
                {
                    max = Math.max(max, A[j][j+k] + A[j+k][j+d]);
                }
                A[j][j+d] = max;
                System.out.println("A[" + j + "][" + (j+d) + "] = " + A[j][j+d]);
            }
        }
        
        // This should be the max profit
        System.out.println(A[0][n-1]);
        return;
    }
}