CoinChange.py

def count(S, m, n ):

	if (n == 0):
		return 1

	if (n < 0):
		return 0;

	if (m <=0 and n >= 1):
		return 0

	return count( S, m - 1, n ) + count( S, m, n-S[m-1] );

arr = [1, 2, 3]
m = len(arr)
print(count(arr, m, 4))