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# 384.Shuffle-an-Array

## 题目描述

Shuffle a set of numbers without duplicates.
Example:
// Init an array with set 1, 2, and 3.
int[] nums = {1,2,3};
Solution solution = new Solution(nums);
// Shuffle the array [1,2,3] and return its result. Any permutation of [1,2,3] must equally likely to be returned.
solution.shuffle();
// Resets the array back to its original configuration [1,2,3].
solution.reset();
// Returns the random shuffling of array [1,2,3].
solution.shuffle();

## 代码

### Approach #1

class Solution {
private int[] array;
private int[] original;
private Random rand = new Random();
public Solution(int[] nums) {
array = nums;
original = nums.clone();
}
/** Resets the array to its original configuration and return it. */
public int[] reset() {
array = original;
original = original.clone();
return array;
}
/** Returns a random shuffling of the array. */
public int[] shuffle() {
List<Integer> aux = getArrayCopy();
for (int i = 0; i < array.length; i++) {
int removeIdx = rand.nextInt(aux.size());
array[i] = aux.get(removeIdx);
aux.remove(removeIdx);
}
return array;
}
private List<Integer> getArrayCopy() {
List<Integer> asList = new ArrayList<Integer>();
for (int i = 0; i < array.length; i++) {
}
return asList;
}
}
/**
* Your Solution object will be instantiated and called as such:
* Solution obj = new Solution(nums);
* int[] param_1 = obj.reset();
* int[] param_2 = obj.shuffle();
*/

### Approach #2 Fisher-Yates Algorithm

class Solution {
private int[] array;
private int[] original;
Random rand = new Random();
public Solution(int[] nums) {
array = nums;
original = nums.clone();
}
public int[] reset() {
array = original;
original = original.clone();
return original;
}
public int[] shuffle() {
for (int i = 0; i < array.length; i++) {
swap(i, rand.nextInt(array.length - i) + i);
}
return array;
}
private void swap(int i, int j) {
int temp = array[i];
array[i] = array[j];
array[j] = temp;
}
}