import java.util.Map;
import java.util.HashMap;


class MapExample {

///////////////////////////////////////////////////////////////////////////////////
    /* Computes the nth fibonacci number using bottom-up Dynamic Programming. */
    static long dpfib(int n) {
        if (n < 2)
            return n;
        long[] table = new long[n+1];
        table[0] = 0; table[1] = 1;
        for (int i = 2; i <= n; i++)
            table[i] = table[i-1] + table[i-2];
        return table[n];
    }

///////////////////////////////////////////////////////////////////////////////////

    /* Precondition: n >= 0
     * Computes the nth fibonacci number using Memoization.
     */
    static long mpfib(int n) {
        Map<Integer, Long> table = new HashMap<Integer, Long>();
        
        // Computes f(n) using the recurrence & the table.
        return memoize(n, table);
    }

    /* Precondition: n >= 0 */
    static long memoize(int n, Map<Integer, Long> table) {
        Long val = table.get(n);
        if (val == null) {
            if (n < 2) {
                table.put(n, (long)n);
            } else {
                table.put(n, memoize(n-1, table) + memoize(n-2, table)); 
            }
        }
        return table.get(n);
    }


    public static void main(String[] args) {
        for (int n = 0; n < 20; n++) {
            System.out.printf("dpfib(%d) = %d, ", n, dpfib(n));
            System.out.printf("mpfib(%d) = %d%n", n, mpfib(n));
        }
    }
}