try: import psyco psyco.full() except ImportError: pass def count_changes(amount_cents, coins): n = len(coins) # max([]) instead of max() for Psyco cycle = max([c+1 for c in coins if c <= amount_cents]) * n table = [0] * cycle for i in xrange(n): table[i] = 1 pos = n for s in xrange(1, amount_cents + 1): for i in xrange(n): if i == 0 and pos >= cycle: pos = 0 if coins[i] <= s: q = pos - coins[i] * n table[pos]= table[q] if (q >= 0) else table[q + cycle] if i: table[pos] += table[pos - 1] pos += 1 return table[pos - 1] def main(): us_coins = [100, 50, 25, 10, 5, 1] eu_coins = [200, 100, 50, 20, 10, 5, 2, 1] for coins in (us_coins, eu_coins): print count_changes( 100, coins[2:]) print count_changes( 100000, coins) print count_changes( 1000000, coins) print count_changes(10000000, coins), "\n" main()