Well, you did say "how often", which is probably a pretty stupid way of phrasing the problem. It certainly led me to think that the problem involved repeated changings, e.g. once I've broken it into two 50s, what can I do with the two 50s. It now seems that you meant to say "How many ways", rather than "How often". I mean, *how often?* Once per day? Twice per second?
| [reply] |

| [reply] |

Sorry, I can not express it any better. Look at the example please. The answer, 50 is correct. I think 'How many ways' is good. Just search for any combination of 100, 50, 20 , 10 and 5 euro notes where the sum is 100 without repeating a combination. I hope it is clearer to you now.
| [reply] |

Okay...now I understand the problem. If I dust of my math degree...I think this could be solved with generating functions. Basically, calculate (x+ x**5+ x**10 + x**20 + x**50 + x**100)**100 and find the coeffieient of x**100 in the resulting polynomial. Easy...;)
thor
`
Feel the white light, the light within`
Be your own disciple, fan the sparks of will
For all of us waiting, your kingdom will come
| [reply] |

Comment onRe^2: How to generate restricted partitions of an integer