package me.evyatar.first;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map.Entry;

public class Ackermann {

    public static HashMap<String, Integer> repetition = new HashMap<>(),
                                           values = new HashMap<>();
    public static int total = 0;

    public static int Ackermann(int x, int y) {
        String str = String.format("(%s, %s)", x, y);
        Integer i;



        if ( ( i = repetition.get((str))
                ) == null) {
            repetition.put(str, 1);
        }
        else {
            repetition.put(str, i+1);
            return values.get(str);
        }

        total++;

        if (x == 0)
            values.put(str, i = y+1);
        else if (y == 0)
            values.put(str, i = Ackermann(x-1, 1));
        else
            values.put(str, i = Ackermann(x-1, Ackermann(x, y-1)));

        return i;
    }

    public static void main(String[] args) {
        System.out.println(Arrays.asList(args));

        System.out.println(String.format("(%s, %s)", 1, 2));
        System.out.println(Ackermann(3, 8));


        System.out.println("Statistics: ");

        for (Entry<String, Integer> e : repetition.entrySet()) {
            System.out.println(String.format("%s used %s times", e.getKey(), e.getValue()));
        }

        System.out.println("Total computations of " + total);
    }
}