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anupsavvy/Puzzle.java

Created July 27, 2011 03:49
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Write a method to shuffle a deck of cards. It must be a perfect shuffle – in other words, each 52! permutations of the deck has to be equally likely. Assume that you are given a random number generator which is perfect.
Raw
Puzzle.java
public class Puzzle {
public static int[] shuffleCards(int[] cards){
if(cards == null || cards.length==1 || cards.length==0){
return cards;
}
int cardNumber,hold;
for(int i =0; i < cards.length; i++){
cardNumber = (int)(Math.random()*(cards.length-i)) + 1;
hold = cards[cardNumber];
cards[cardNumber] = cards[i];
cards[i] = hold;
}
return cards;
}
}
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