TopCoder problem "ThirtyOne" used in SRM 194 (Division I Level One , Division II Level Two)



Problem Statement

    

Thirty One is a card game for 2 or more players. The game can be played with one or more decks of standard cards. The aim of the game is to try and make the value of your hand as close to 31 points as possible without going over 31 points. A hand consists of exactly 3 cards.

Each number card (2, 3, ... 9, 10) is worth the value written on the card; Jack (J), Queen (Q) and King (K) are all worth 10; while an Ace (A) is worth either 1 or 11 depending on which will give a greater total without going over 31 points. There is one exception however; if a hand consists of 3 identical cards then the value of that hand automatically becomes 30.5 points.

Each element in hands will contain exactly three cards, where cards are separated by exactly one space. For example "A 10 K" is a hand consisting of Ace, 10 and King. The value of this hand is 11 + 10 + 10 = 31. Note that we chose Ace to be 11 and not 1 since that gives us a greater total without exceeding 31.

Given a String[] of players' hands return the index of the winning player, where element i (0-indexed) in hands belongs to player i. If two or more players are tied for the lead then return the player with the lower index.

 

Definition

    
Class:ThirtyOne
Method:findWinner
Parameters:String[]
Returns:int
Method signature:int findWinner(String[] hands)
(be sure your method is public)
    
 

Constraints

-hands will contain between 2 and 50 elements inclusive.
-each element in hands will have exactly three cards, where cards are separated by exactly one space add that there are no leading/trailing spaces.
-cards in hands will be 2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A.
 

Examples

0)
    
{"10 A A", "K 2 3"}
Returns: 0
The value of the first hand is 10 + 11 + 1 = 22. Notice that we chose the last Ace to be 1, otherwise our total would have been over 31. The value of the second hand is 10 + 2 + 3 = 15. The first hand is closer to 31 so it wins.
1)
    
{"2 3 4", "10 6 8", "A K 3"}
Returns: 1
The value of the first hand is 2 + 3 + 4 = 9. The value of the second hand is 10 + 6 + 8 = 24. The value of the third hand is 11 + 10 + 3 = 24. However the second hand wins since it comes earlier than the third hand.
2)
    
{"J 5 2","2 7 5","10 J 2","J 6 2","J Q K"}

Returns: 4
3)
    
{"Q K K", "10 J Q", "A 8 A", "2 2 2"}
Returns: 3
The last hand has three identical cards so its value is 30.5
4)
    
{"Q 6 6","7 8 3","3 7 2","K Q 6","Q 6 3","5 3 8","10 J Q","4 8 4","Q 2 5","8 A 8",
"9 10 10","2 K 5","10 4 5","Q 4 Q","3 J 2","7 4 4","3 9 7","A 4 4","Q 7 7","10 9 A",
"J 3 5","5 8 9","Q Q 7"}

Returns: 6

Problem url:

http://www.topcoder.com/stat?c=problem_statement&pm=2422

Problem stats url:

http://www.topcoder.com/tc?module=ProblemDetail&rd=5069&pm=2422

Writer:

dimkadimon

Testers:

lbackstrom , brett1479

Problem categories:

String Parsing