Day24.java

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashSet;

public class Day24 {
	public static void readInput(String fname,long[] A,long[] B,long[] C) throws IOException {
		BufferedReader brdr=new BufferedReader(new FileReader(fname));
		for (int w=0;w<14;++w) {
			for (int i=0;i<4;++i)
				brdr.readLine();
			C[w]=Integer.parseInt(brdr.readLine().split(" ")[2]);

			A[w]=Integer.parseInt(brdr.readLine().split(" ")[2]);
			for (int i=0;i<9;++i)
				brdr.readLine();
			B[w]=Integer.parseInt(brdr.readLine().split(" ")[2]);
			brdr.readLine();
			brdr.readLine();
		}
	}
	public static  void recursiveSolution(int w,long[] A,long[] B,long[] C,long Z,String solution,int allowedRises) {
			if (w==14) {
				if (Z==0)
					System.out.println(solution+" "+Z+" "+allowedRises);
			}
			else {
				long OZ=Z;
				Z/=C[w];
				 for (long d=9;d>=1;--d) {
					 if (((OZ % 26) + A[w])==d) 
						 recursiveSolution(w+1,A,B,C,Z,solution+d,allowedRises);
					 else 
						 if (allowedRises>0) 
							 recursiveSolution(w+1,A,B,C,26*Z+B[w]+d,solution+d,allowedRises-1);
				}
			}
	}  
	
	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		/*
		 * That was not a nice task
		 * txt just calls  a function 14 times with three possible alterations at each step
		 *  this leads to an update of Z as follows
		 *  		-Z[i] = Z[i-1] / C[i]  if (Z[i-1] % 26) + A[i]==w[i]  
		 *  		-Z[i] = Z[i-1/ C[i]  + 26*Z[i-1] + B[i] +W[i]   otherwise
		 *  
		 *  simulate this procedure cutting when applicable
		 */
		String REAL="input/day24.txt";
		long[] A=new long[14];
		long[] B=new long[14];
		long[] C=new long[14];

		readInput(REAL,A,B,C);
		for (int i=0;i<14;++i)
			System.out.print(C[i]+" ");
		System.out.println();
		recursiveSolution(0,A,B,C,0,"",7); 
		//there only seven divisions by 26 
		//B[i] + W[i] are always positive  so only division can bring Z[i] closer to 0
		//if we multiply by 26 more than 7 times, we can never end up to 0
	}

}