Off-by-one Error In Perfect Shuffle Method

I am supposed to create a method that simulates a perfect shuffle of a given array of integers. According to the assignmment, this is what a perfect shuffle is:

This procedure is called a perfect shuffle if the interleaving alternates between the two half-decks.Unfortunately, the perfect shuffle comes nowhere near generating all possible deck permutations.In fact, eight shuffles of a 52-card deck return the deck to its original state!Consider the following perfect shuffle algorithm that starts with an array named cards that contains 52 cards and creates an array named shuffled.

Initialize shuffled to contain 52 empty elements.
Set k to 0.
For j = 0 to 25,
− Copy cards[j] to shuffled[k];
− Set k to k+2.
Set k to 1.
For j = 26 to 51,
− Copy cards[j] to shuffled[k];
− Set k to k+2.

This approach moves the first half of cards to the even index positions of shuffled, and it moves the second half of cards to the odd index positions of shuffled.The above algorithm shuffles 52 cards. If an odd number of cards is shuffled, the array shuffled has one more even-indexed position than odd-indexed positions. Therefore, the first loop must copy one more card than the second loop does. This requires rounding up when calculating the index of the middle of the deck. In other words, in the first loop j must go up to (cards.length + 1) / 2, exclusive, and in the second loop j most begin at (cards.length + 1) / 2.