Efficient array elements un-ordering in Java
I just wanted to know what is the best way to un-order th开发者_Go百科e elements in an ordered array in Java, Thanks
I think you want Collections.shuffle(List)
? If not that, you will need to give us more details about what you're trying to do.
You want to shuffle that array using a good algorithm.
I would trust Collections#shuffle to implement this properly. If you need it to work on the array directly, implement the algorithm in your own helper method.
I don't know much Java, so there may be better way, but this'll do the trick nicely.
Fisher-Yates shuffle from Wikipedia:
static Random rng = new Random();
public static void shuffle(int[] array) {
// i is the number of items remaining to be shuffled.
for (int i = array.length; i > 1; i--) {
// Pick a random element to swap with the i-th element.
int j = rng.nextInt(i); // 0 <= j <= i-1 (0-based array)
// Swap array elements.
int tmp = array[j];
array[j] = array[i-1];
array[i-1] = tmp;
}
}
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