(UVA) Y2K Accounting Bug - Solution

Link to the problem: https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=24&page=show_problem&problem=1517

The solution below used Backtracking to solve this problem.


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

class Main {
    public int s;
    public int d;
    public int maxSurplus;
    public int[] register;
   
    public void rec(int month, int surplus, int lastFive) {
        if (month >= 5) {
            if (lastFive >= 0) {
                return;
            }
        }
        if (month == 12) {
            maxSurplus = Math.max(maxSurplus, surplus);
            return;
        }
               
        register[month] = s;
        rec(month+1, surplus+s, lastFive + s - (month >= 5 ? register[month-5] : 0));

        register[month] = d;
        rec(month+1, surplus+d, lastFive + d - (month >= 5 ? register[month-5] : 0));
    }
   
    public void process() throws NumberFormatException, IOException {
        Scanner sc = new Scanner(System.in);
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        while (sc.hasNext()) {
            s = sc.nextInt();
            d = sc.nextInt();
            d *= -1;
           
            maxSurplus = Integer.MIN_VALUE;
            register = new int[12];
            rec(0, 0, 0);
           
            String answer = (maxSurplus < 0) ? "Deficit\n" : maxSurplus+"\n";
            bw.write(answer);
        }
          
        bw.flush();
        bw.close();
       
        return;
    }
   
    public static void main(String[] args) throws NumberFormatException, IOException {
        Main m = new Main();
        m.process();
       
        System.exit(0);
    }
}