### PS3: Problem 4 » Solution

May. 7th, 2010 10:26 am**aranthe**

Oops! I almost forgot about problem 4. I didn't have time to attempt a recursive solution for this one. (Off the top of my head, I think the key would be to encapsulate the loop portion into a recursive function, rather than to make the entire `subStringMatchExactlyOneSub`

function recursive.) If you've done one, please post it.

#### PS3: Problem 4 » Solution

def subStringMatchExactlyOneSub( key, target ): subOneMatches = sorted(subStringMatchOneSub( key, target )) exactMatches = sorted(subStringMatchExact( target, key )) exactOneMatches = () for subOneMatch in subOneMatches: if subOneMatch not in exactMatches: exactOneMatches += subOneMatch, return exactOneMatches